No More Global Rules: What Would A US-México Armed Conflict Look Like in 2026?

With escalating tensions between México and the United States, questions about how a U.S.-México military conflict would look like have started to surface. Although it remains unlikely that a full-scale war breaks out between the countries, the growing threat of the Trump administration taking unilateral military action against drug cartels in México continues to grow each day.

Before the United States invaded Venezuela on January 3rd without Congressional and UN authority and “without even a plausible legal rationale,” the possibility of direct U.S. military action in México seemed remote.

As Trump senior aide, Steven Miller told CNN’s Jake Tapper, the U.S. now believes that global order is “governed by strength, is governed by force, is governed by power,” upending eight decades of global rules governing the use of military force against other nations.

Any unilateral military action by the U.S. would have second and third-level consequences against the United States and has the potential to increase to the level of cross border direct encounters between both militaries resulting in civilian and military casualties. Not withstanding the potential to grow into border skirmishes, any U.S. unilateral military action would likely devolve into economic and political disengagement ending Mexican cooperation on border security, encouraging China or Russia to increase their force projection in the region and be costly to America’s economy.

There are no known war plans for invading México but political rhetoric about intervening militarily against the drug cartels has forced the Mexican government to assuage fears that U.S. military intervention in México was imminent.

The continued discussions about military action in México lead to the question – what would it look like?

Public reports suggest that the Trump administration has been developing plans for potential intelligence and military operations in México. It is assumed that the drug cartels would be targeted through surgical strikes. What is not publicly known is what an armed conflict between the two nations look like. The likely scenario, if conflict were to erupt, will likely be limited to cross border sorties and closed borders with limiting actual combat operations in a limited battlespace.

Although war plans for México, if they exist, have not been made public, an August 15, 2025, article, in Rolling Stone suggested that the Trump administration has drawn up plans. The magazine suggests that “actual operational planning” on the use of the U.S. military exist. The Rolling Stone report supports the scenario that U.S. military intervention would target the drug cartels while a direct invasion of the country is not actively being considered under the current plans offered by military planners.

If what Rolling Stone suggests is true, the latest war plans would follow War Plan Green that envisioned an invasion of México by U.S. forces.

War Plan Green

Starting in 1904, the U.S. kept hypothetical war plan scenarios against several countries, many of them U.S. allies. Drawn up before the outbreak of World War II, the U.S. military created the “Rainbow Five” plans that detailed how the U.S. military would respond to a war with another country. The war plans were color-coded according to country. Some of the original color codes included red for Great Britain, black for Germany, orange for Japan, crimson for Canada and green for Russia. The color white was used for war planning insurrection within the United States.

As the number of scenarios grew, colors changed as new countries were added to the plans. Russia was changed to purple and green was used for México.

As technologies changed and geopolitics evolved, the color-coded war plans were updated. Plan Green had three revisions: 1919, 1919, A-1929 and B-1929. Under the latter, the first mission was to “establish order and [a] stable government” throughout México, labeled “Green” in the war planning documents. The military’s mission under the first scenario was “to invade, occupy, and pacify” México while “maintaining a military Government until a stable, responsible Green government can be established.” This plan was for the potential response to a “hostile” Mexican government.

Under the war plan, the Mexican port of Veracruz would be seized to stop weapons imports. U.S. forces would engage Mexican forces near the Brownsville-Laredo area, with U.S. troops preparing an offensive from the El Paso, Texas area to march towards Mexico City. The U.S. War Department in 1940 estimated that it would require 140,000 U.S. troops for the plan. Seizing the Tampico-Tuxpan oil fields were one of the objectives of the war plan.

If pacifying México after occupying Mexico City, Veracruz and the oil fields had not been achieved, the war plan called for the U.S. to blockade Mexican ports to pressure the Mexican resistance to capitulate through economic pressures.

Common to all three versions was to use of the U.S. Army to protect the border.

The plan was cancelled in 1946 after México joined the ally efforts against Nazi Germany during World War II.

Other than a known informal war game, there does not appear to be any serious war planning for an invasion of México by U.S. military forces. The so-called tabletop exercise published on February 27, 2025, by the nonprofit Win Without War Education Fund war gamed “What Happens if Trump Bombs Mexico?” It used American and Mexican experts to war game the scenario where the Trump administration uses U.S. military forces against Mexican drug cartels.

“What Happens if Trump Bombs Mexico?” War Game

The war game sought answers to fentanyl trafficking, migration, drug cartels civilian safety/prosperity on both sides of the border, the economies of both countries and U.S.-México relations after Trump orders military strikes against Mexican targets.

The war game scenario exposed many “unforeseen consequences” after a U.S. unilateral surgical strike on a drug cartel, “the surprised planners.” Growing violence against the Mexican population was the first result of the strikes as clashes between drug cartels and against Mexican federal forces escalated into the streets displacing Mexicans as the violence grew.

Mexicans outside of the war zones were also affected by growing economic instability as grew from retaliatory tariffs and trade disruptions. But the consequences were not limited to Mexican civilians as trade disruptions caused consumer goods prices to jump and the other trade disruptions disrupt U.S. factories, including effectively shutting down car manufacturing.

The war game suggested that the Mexican government would retaliate by ratcheting up retaliatory tariffs and expelling all law enforcement and military personnel shutting off cooperation in drug trafficking interdictions and shutting down diplomatic relations. Another consequence of the unilateral strike(s) was the Mexican government ended cooperation on immigration policies.

The war game revealed that the Sheinbaum government would consider entreaties from China, taking advantage of the situation, including refueling agreements for the Chinese Navy.

As other past drug interdictions have already demonstrated, the targeting cartel leaders only resulted in rising cartel violence with little impact on the drug crossing the border. Thus, the war game suggested that in addition to the disruption of America’s economy, cartel violence only helped to intensify the humanitarian crisis without resulting in a measurable reduction of drug entering the country.

It is generally assumed that a full-scale invasion of México is not tenable because of the resources it would require and the economic and political ramifications, in addition to a breakdown of the Mexican society that would lead to instability further pressuring U.S. security forces along with the humanitarian costs involved. Rather than solving the drug cartel problem, full-scale military action in México would be costly to the American people.

The war game suggested that even a limited and targeted strike on Mexican soil against the drug cartels would result in costly retaliation and further empower the cartels instead of curtailing drug trafficking into the U.S.

Before looking at a potential Order of Battle, it is useful to understand the political dynamics driving such a scenario forward.

The Cause Célèbre for War with México

Using military force against México started during the Trump administration’s first term but was largely overshadowed by the administration’s build the wall narrative. Nonetheless it remained part of the overall Trump administration political arsenal. The conservative think tank behind Project 2025, a blueprint for the Trump administration on governing for his second term published a special report on January 27, 2025, outlining how the federal government can secure the U.S.-México border with the military.

Although the report focused on using the military for border security, it supported its argument by stating that “it is increasingly clear that the Chinese Community Party is actively funding and deploying America’s most deadly drug threat,” fentanyl. Although suggesting that “joint military action, coordinated with approval from the Mexican government, is the ideal condition for any direct U.S. action against the cartels on Mexican territory,” it added that “cooperation with Mexico has rapidly deteriorated.”

The report argued that “options for direct action against the cartels within Mexico should be a last resort and operated on an escalating scale, to be deployed in consideration of the present operating environment and diplomatic context.”

The report suggests that “lower-risk options” like enhanced military presence on the border should include “planning for more aggressive measures, including on Mexican territory.” The report goes on to argue that “joint military action, coordinated with the approval of the Mexican government, is the ideal condition.” As Mexican president Claudia Sheinbaum has said, Trump consistently argues for coordinated U.S.-México military operations, which the Mexican president firmly rejects. The report adds that “in the appropriate context, unilateral U.S. military action may be employed to disrupt cartel activity and prompt cooperation from a resistant Mexican government.”

Dear reader, I hope you appreciate this article. Before reading more, I ask that you consider my work and make a small donation to help keep this publication open for everyone. El Paso lacks news diversity. I offer 20+ years of historical knowledge about El Paso’s politics and public policy. Media diversity matters. Make a small donation today to help keep my work going for another 20+ years. Thank you.

However, the report goes on to recognize “that there are high risks of undesirable response from the Mexican government and drug cartels,” arguing that the Trump administration take “coordinated measures to mitigate undesirable responses and limit the exposure [of] the U.S.”

Much of what has been deployed by the Trump administration to date are part of the report’s “less provocative” military actions. These include aerial surveillance of México, which began in early 2025. It adds that one of the first steps is to designate drug cartels Foreign Terrorist Organizations (FTOs). In February 2025, the Trump administration designated several cartels as FTOs.

After aerial surveillance, the report proposes deploying U.S. drone strikes on “non-human targets” like jamming devices the cartels have begun to deploy to counter U.S. interdiction activities.

The think-tank report, though, goes on to state that military strikes in México and the use of special operators in the country has “the potential to provoke severe backlash from the Mexican government, as well as likely reprisals and escalation from the drug cartels.” As the report points out, there “are reasons to doubt the effectiveness” of any unilateral U.S. military action. Against the potential for “blowback,” any U.S. military action must be preceded by “substantial bolstering of the U.S. military presence along the border,” and the action “should also account for potential threats to the more than one million U.S. ex-pats living or working” in México, states the report. It adds that “Americans firms operating in Mexico may also face risks both from cartel violence and government financial punishment, including expropriation.”

Nonetheless, the potential for a unilateral strike remains forcing us to consider what a likely scenario would be like. To do so we must first understand the Mexican military capability in an Order of Battle.

The Mexican Order of Battle for 2026

An Order of Battle (ORBAT) is a military document showing the military structures of belligerent parties including their command structure, military strengths and deployments, and military equipment that can be deployed in a battlespace. Battlespace is where military engagements are likely to occur.

Before going into the Order of Battle it is important to note that outright war between the two nations is highly unlikely for political and economic reasons. Economically, any hostilities between both nations would lead to serious economic repercussions for both countries because México is now America’s leading trading partner. The economic disruption would create problems for the Trump administration. This is further demonstrated by the war game described above and Plan Green shows that occupying México has been unfeasible since the 1920’s because of the immense resources it would take to control the large population and impose security on the large land mass.

Putting aside the limitations we can use the ORBAT to understand that capabilities of the Mexican armed forces.

México ORBAT: Command & Structure

The Mexican president is the supreme commander of the armed forces. Under the president are two ministries that oversee the armed forces. The first is the Secretaría de la Defensa Nacional (SEDENA) that oversees the army and the air force. The second is the Secretaría de Marina (SEMAR) oversees the naval forces.

México ORBAT: Force Composition

The total active military force is just under 400,000 active military personnel. This includes around 275,000 army troops, 92,000 naval personnel and around 30,000 air force personnel. The National Guard is counted among the army personnel. The military includes ground forces, air assets and naval forces.

Ground Forces

The Mexican Army is structured into 12 military regions and 44 military zones dispersed across the nation. The Army’s combat units include artillery regiments, light-armored units and infantry and motorized cavalry. The operational command structure is brigade level with corps-level formations. Special forces groups are part of the Army.

The National Guard provides border and domestic security for the Army.

Air Capabilities

The Fuerza Aérea Mexicana (FAM) is part of the Army. It operates a fleet of several hundred aircraft and helicopters largely used for drug interdiction operations and transportation. The air force provides limited strategic airlift, and its force projection is limited to the country’s airspace. It also has reconnaissance and ground operations capabilities. The air force has limited airspace security capabilities.

Naval Forces

The Armada de México maintains several patrol vessels, frigates, smaller combatants and coastal security assets. Its primary focus is drug interdiction and protecting maritime zones.

México ORBAT: Operational Capability Against a U.S. Military Sovereignty Violation

The Mexican armed forces are primarily organized for internal security, disaster response and combating transnational organized crime. In recent years it has taken up additional roles in airport and customs operations. Although it maintains sovereignty defense capabilities it is not equipped for large-scale conventional warfare.

Against the United States the Mexican military lacks heavy weaponry, advanced aircraft systems and strategic missile capabilities. México’s air assets are focused on surveillance and troop logistics and are not capable of air superiority missions and have limited short range bombing capabilities.

The Mexican Navy lacks a blue-water fleet limiting its power projection capabilities.

Force projection beyond its borders is nonexistent and military personnel lack the capability for high-intensity combat operations.

The Mexican military’s strengths are its large internal security capability from its historical role of internal security and narcotrafficking missions. It is well dispersed across México and is experienced operating coordinated task forces and urban warfare.

In the rural open country, the Mexican military is incapable of resisting U.S. military operations but in densely populated areas, the Mexican military has the equipment and training to resist U.S. military operations by limiting the use of heavy and strategic weapons systems the U.S. military normally deploys in combat.

México’s response to a unilateral intervention by U.S. military forces – even if limited to targeted strikes against drug cartel leadership – would be the mobilization of its military to defend territorial sovereignty. The Mexican military would avoid direct conventional warfare and use its geographic experience with militia-style asymmetric warfare to impede U.S. operations by limiting U.S. conventional capabilities.

The government of México would leverage economic, political and diplomatic avenues as part of its defensive strategies. It is likely that direct military-to-military operations would be guerilla tactics in urban settings rather than direct combat operations thereby limiting the U.S. military’s technological and heavy weapons capability and making combat operations for the U.S. costly in each engagement. (ORBAT prepared by Martín Paredes from public sources.)

How Likely Is War?

Although the political rhetoric continues to suggest that unilateral U.S. military intervention is likely, the likelihood of it remains unlikely. The Trump administration’s evolving threats against Mexican sovereignty have now evolved into allowing the U.S. military a larger role in cartel operations in México in coordination with Mexican authorities.

The pressure to allow the U.S. a larger role in drug interdiction operations suggests that Trump and Sheinbaum may be negotiating a detente where both governments proclaim victory through cooperation.

Furthermore, the Trump administration seems to be slowly shifting away from direct unilateral military operations and instead pressuring the Sheinbaum administration by using the threat of ending the ongoing USMCA review negotiations by calling them “irrelevant” to the U.S.

The operating keyword to the issue is “unilateral” military strikes because there is a long history and framework for U.S. military forces operating in México and even in the U.S.

All such operations have operated under the framework of cooperation and law enforcement activities and agreed to by the Mexican government.

Using the military for drug interdiction efforts carries the risk of second and third order effects that can get out of control quickly. Any unilateral military action without the consent of Sheinbaum will force her to react to U.S. military forces inside of México because of public pressure.

Also, because of the drug cartels’ history of adopting and surviving eradication attempts for decades, they have created an infrastructure that uses remote and urban areas to protect their greater assets against attack. Attempting to use small counterterrorism teams by U.S. forces in México would bog down and eventually leading to civilian and even U.S. military casualties increasing political pressure on both sides to respond with greater force that would eventually lead to a complex irregular war.

The U.S. military is no longer experienced in irregular warfare because since for the last 15 years it has been focused on high-end warfare against an adversary like China. Simply put, the U.S. is no longer trains for counterinsurgency (COIN) operations. Meanwhile, the Mexican military has been laser focused on COIN operations since the early 1950’s and have been waging war against the drug cartels through COIN-led operations.

The disparity between both militaries both in material and operational focus will lead to second and third order consequences after any unilateral operation by U.S. forces in México.

Second and third order consequences include but are not limited to reproachment from the international community, loss of American influence in global affairs and accusations of violations of laws; domestic, international, maritime and armed conflict laws. Another consequence would be empowering both China and Russia to continue to expand their own spheres of influence in the hemisphere. The cost to the American economy would be consequential from the likely retaliation from México, possibly Canada and other countries and the expense of the war itself. From the perspective of addressing the drug problem, the consequences would be further splintering drug cartels into smaller and more dynamic groups that increase drug production to recover losses, rearm and strengthen against further targeting by U.S. forces.

Additionally, it is clear that the American people are not willing to support rising economic pressures and another forever irregular war with rising casualties.

The U.S. military’s action to capture Nicolás Maduro on January 3rd reenforces this. The American task force successfully penetrated Venezuelan defenses, captured and removed Maduro from Venezuela. The operation took at least 150 aircraft and hundreds, if not thousands of personnel and an untold number of munitions, some costing hundreds of thousands of dollars each. The result is Maduro and his wife re in U.S. custody but leaving the Maduro’s regime intact.

The Venezuelan operation’s limited scope exposes that the U.S. military is unable to mount a credible military force capable of occupying a country like Venezuela or México for that matter. However, an operation invading México would be easier in terms of logistics because the operations would originate from land bases in the United States substantially reducing force projection logistics. But the American military continually faces difficulty against an entrenched insurgency in any theater of operation.

But the economic impact on both nations is likely the largest impediment to a unilateral strike on Mexican territory by the Trump administration.

America’s two largest trading partners today are México followed by Canada showing that disrupting USMCA would be economically devastating to the American consumers. Both previous Democratic and Republican presidents have supported military operations in Latin American countries. The difference being that U.S. military operations in Colombia and México have been largely advisory and/or supportive of their host countries, and with their active approval for the operations.

At the end of the day, solving America’s endemic drug problem leads any discussion of an American unilateral military intervention against the drug cartels raising the question, would it solve the drug problem?

Will It Work?

The historical record clearly shows that decapitating drug cartel leadership does not impact drugs entering the country. On the contrary, the fragmentation of the drug cartels not only increases violence but makes it harder to control as more illicit operators rise from the ashes. Furthermore, underestimating Mexican nationalism ignores the second-order consequence of likely support for punitive retaliation against American interests economically and physically even it becomes costly to the Mexican populations. Furthermore, the likely cartel retaliation would become symbols of resistance to perceived U.S. imperialism, further empowering the drug cartels against American interests.

Notwithstanding plenty of evidence showing that any unilateral military intervention by the U.S. against the Mexican state would be painful to both countries, the threat remains high. Yesterday the Federal Aviation Administration issued a NOTAM (Notices to Airmen) advising that all pilots, including commercial pilots, to be aware “for potentially hazardous situation” in and around México, “due to military activities” and GPS interference. The NOTAM is scheduled to last until March 17, which is routine in NOTAMs like this one. But a similar NOTAM was issued in November for the Venezuelan airspace, before the Maduro U.S. military operation.