Trump’s Evolving Approach to Military Force: A Departure from the Powell Doctrine

When bombs began falling on Iran this weekend, most Americans were as surprised as the rest of the world. The U.S. Force posture in the Middle East had been building in the preceding weeks, but negotiations between Washington and Tehran were still underway. Even as the U.S. Military readied for an attack, the Trump administration obscured the exact objective. There was remarkably little national debate, scant discussion with U.S. Allies, and no vote in Congress about the desirability of conflict. Two days into the war, administration officials have yet to articulate a specific vision for how it will end. Instead of employing decisive force, U.S. President Donald Trump is prioritizing flexibility. This stance reflects a new approach to the use of force—visible across multiple Trump interventions, from the Red Sea to Venezuela—that inverts traditional thinking.

The Anti-Powell Doctrine

in many ways, Trump’s use of force is the inverse of the Powell Doctrine. Developed during the Gulf War (1990–91) by General Colin Powell, who later served as Secretary of State, the Powell Doctrine held that force should be a last resort, employed only after all nonviolent means have been exhausted. If war is necessary, it should pursue a clear objective, with a clear exit strategy, and with public support. It should employ overwhelming, decisive force to defeat the enemy, utilizing every available resource—military, economic, political, and social.

Derived from the lessons of Vietnam, the approach was designed to avoid protracted conflicts, high death tolls, financial losses, and domestic divisions. As Powell later wrote, military leaders could not “quietly acquiesce in halfhearted warfare for half-baked reasons that the American people could not understand or support.”

The Powell Doctrine, building on criteria established by Defense Secretary Caspar Weinberger in the 1980s, spurred debate from the start. Some critics thought the all-or-nothing approach would preclude tailored force for modest goals. Supporters believed that was precisely the point, viewing interventions like those undertaken by the Clinton administration in Somalia, Haiti, and the former Yugoslavia as misuses of military power risking failure or quagmire.

Testing the Doctrine: Afghanistan and Iraq

The U.S. Invasions of Afghanistan in 2001 and Iraq in 2003 were key tests of the Powell Doctrine. The George W. Bush administration sought to apply it in both cases. War was declared only after the Taliban and Iraqi leaders ignored U.S. Demands, and the president sought to persuade Americans that the decisions to proceed to war were wise. The stated objectives were clear: to eliminate the safe haven the Afghan government was providing al-Qaeda and to rid Iraq of weapons of mass destruction. Congressional authorization was also sought and received in both cases.

In Afghanistan, U.S. Forces combined air attacks with support for fighters in the Northern Alliance, which overthrew the Taliban. In Iraq, 160,000 U.S. Troops launched a ground invasion to topple the regime. The planned exit strategy involved turning governing institutions over to exiles, local leaders, and domestic security forces, after which American troops would return home.

However, things did not go according to plan in either case. Attempts to avoid prolonged conflicts resulted in them anyway. The wars proved costly and divisive, and their objectives shifted over time. Whether these problems stemmed from a misapplication of the Powell Doctrine or a flawed concept, the shadows of Afghanistan and Iraq have colored every U.S. Military intervention of the past two decades, including the current war in Iran.

The New Force: Trump’s Approach

In an effort to avoid repeating past debacles, the Trump administration has pursued an inverse approach. This new approach began forming in Trump’s first term and has solidified in his second. Actions include missile strikes against the Assad regime in Syria (2017-2018), continued military operations in Iraq and Syria against ISIS, the killing of ISIS leader Abu Bakr al-Baghdadi, a war against the Houthis in Yemen, attacks on Iranian nuclear sites, and an invasion of Venezuela to seize Nicolás Maduro. Just two days ago, a major operation was launched in Iran.

These operations depart from traditional uses of force. The Powell Doctrine holds that war should be a last resort, after political, diplomatic, and economic means have failed. Presidents George H.W. Bush and George W. Bush gave ultimatums before beginning hostilities. Trump’s approach uses ambiguity as an advantage, catching opponents off guard. No public ultimatums were issued to Soleimani or Maduro. For Trump, force is a tool to increase leverage, maximize surprise, and produce outcomes.

Another departure from the Powell Doctrine is the lack of emphasis on public support. The Powell Doctrine views the Vietnam-era protests as a case to be avoided. If an objective is key enough for Americans to fight for, the thinking goes, the people should support it. Establishing such support generally requires the president to make a case, frequently and over months. Congress is expected to demonstrate approval through a vote to authorize force after debate. Where the Powell Doctrine calls for clarity, Trump prizes flexibility. No conflict during Trump’s presidencies has been preceded by a campaign to win public support, and Congress has not voted to authorize any of them. Each conflict began suddenly and followed an unpredictable course.

Objectives and Decisiveness

The Trump administration has also avoided articulating clear objectives for its use of force. When announcing the war with Iran, the president said the objective was “to defend the American people by eliminating imminent threats from the Iranian regime,” despite Tehran not enriching uranium or possessing missiles capable of reaching the United States. Trump has stated both that the goal is regime change in Iran and that he is planning to negotiate with the leadership that replaced the Supreme Leader. He initially claimed pressure on Venezuela was necessary to stop drugs and gang members, then explained the goal was to bring Maduro to justice, recover stolen oil, and align with a new corollary to the Monroe Doctrine. What Americans are fighting for in each country, and how they will know if they attain it, remains unclear.

By claiming multiple and vague objectives, the president retains the ability to stop fighting without admitting defeat. This, rather than obvious victory, is his exit strategy. When announcing attacks on the Houthis, Trump said, “We will use overwhelming lethal force until we have achieved our objective,” with the objective allegedly being to end Houthi attacks on American vessels in the Red Sea. The Houthis, Trump later said, would be “completely annihilated.” A month into the bombing campaign, the administration cut a deal with the group to end its attacks.

Finally, Powell’s dictum calls for overwhelming, decisive force. Trump’s approach favors short, sharp military actions employing airpower and special forces, almost always excluding conventional ground forces. Trump has made clear that the United States will not deploy large-scale ground forces for regime change in Iran.

Good Enough?

The Trump response to the Powell Doctrine has, in some ways, served recent history better than a dogmatic application of the original. Following the limited use of force against the Houthis with a bilateral agreement produced a better outcome than ignoring the attacks on U.S. Shipping. It was also better than using pure military force, as Saudi Arabia and the United Arab Emirates attempted for years. The world is better off without Iran’s nuclear sites at Fordow and Natanz, and without Soleimani leading the Islamic Revolutionary Guard Corps. The jury remains out on Venezuela, but a democratic transition remains possible.

Short, sharp uses of force that preserve flexibility, leverage ambiguity and surprise, minimize the chances of quagmire, and end with a “good enough” outcome might be the best approach in many cases. They are likely not the best approach to all cases, however, and we may soon see the limits of Trump’s way of war. The attack on Iran represents the most ambitious of Trump’s foreign policy gambits to date. Forcing regime change in a country much larger and more populous than Iraq or Afghanistan, through an operation with no ground component, no obvious domestic allies, and facing an entrenched security apparatus, will be extraordinarily difficult. The range of nightmare scenarios—from an IRGC-led military dictatorship to domestic chaos—is wider than the possibility of a democratic uprising.

Here, the president’s flexibility and ambiguity might reveal the way forward. If the United States and Israel are unsuccessful in toppling the Islamic Republic of Iran, if U.S. Forces accept significant casualties, if the American public grows tired of the conflict, or if the alternative to continued regime rule looks even worse, Trump could stop the fight. By claiming that the objective was, from the beginning, to simply weaken Iran and prevent it from obtaining a nuclear weapon, the president could declare victory.

Such a scenario would demonstrate one more limitation of the Trump approach: It does not pave the way for long-term peace but postpones conflict to another day.