Global Agenda: President Trump and the Laws of War

This blog post is part of a series entitled Global Agenda, in which experts will identify major global challenges facing President-Elect Trump, the options available to him, and what is at stake for the United States and its partners. This following post is authored by John B. Bellinger III, adjunct senior fellow for international and national security law at the Council on Foreign Relations. This op-ed is based on the Sixth Annual Lloyd Cutler Rule of Law lecture sponsored by the Salzburg Global Seminar which Mr. Bellinger recently delivered at the U.S. Supreme Court.

When Donald Trump becomes president, he will assume the awesome responsibility of commanding the most powerful military in the world, with U.S. armed forces engaged in combat operations in at least seven countries in the Near East and North Africa. At some point during his presidency, he may consider whether to launch a military attack against another country, such as North Korea or Iran, to defend the United States or its interests. President-Elect Trump and Vice President-Elect Pence should take time early in the administration to be briefed on the domestic and international laws governing the use of military force and the conduct of military operations. Some of these laws are outdated and should be revised or augmented, but the president still must comply with them.

The United States has been in a continuous state of armed conflict for over fifteen years. Presidents Bush and Obama have ordered the use of military force, including deployment of U.S. combat troops and thousands of air strikes, in Afghanistan, Iraq, Libya, Pakistan, Somalia, Syria, and Yemen.

The president has broad powers under the Constitution as Commander-in-Chief, but these powers are limited by domestic statutes and international law. For example, the War Powers Resolution, enacted by Congress in 1973 during the Vietnam War, requires the president to report the introduction of U.S. armed forces into hostilities and to terminate any use of the armed forces within sixty days unless Congress issues a specific authorization. Congress passed specific Authorizations to Use Military Force (AUMF) against those responsible for the 9/11 attacks in September 2001 and against the government of Saddam Hussein in October 2002, but has not revised these authorizations.

With respect to international law, the United Nations Charter, a treaty approved by the Senate in 1945, prohibits the use of force against or in another UN member state except in self-defense against an armed attack or unless authorized by the UN Security Council or the state itself. The charter does not specifically allow a country to use force against a terrorist group that launches attacks from another country or against a government that commits mass atrocities against its own citizens.

Because these laws were not designed to address contemporary problems, recent presidents have sometimes relied on strained interpretations of them to justify their military operations. President Obama informed Congress that the U.S. air campaign against Libyan government forces beginning in March 2011 did not constitute “hostilities” that triggered the War Powers Resolution’s 60-day termination provision because U.S. operations did not involve “sustained fighting or active exchanges of fire with hostile forces.” President Obama later concluded that even though Congress had failed to authorize the use of force against the self-proclaimed Islamic State in Iraq and Syria beginning in 2014, U.S. military actions were specifically authorized by the AUMF passed by Congress more than a decade previously.

When Mr. Trump enters office, he will confront the same legal restrictions faced by his predecessors. In addition to familiarizing himself with the rules that govern use of the U.S. armed forces, he should ask Congress to update U.S. laws.

He should push Congress to enact a comprehensive new authorization against terrorist groups that revises the outdated 2001 AUMF against Al-Qaeda, repeals the 2002 AUMF against Saddam Hussein, and specifically authorizes the use of force against the Islamic State. The new authorization should be broad enough to authorize military force against new groups that pose imminent threats to the United States but include reasonable restrictions on protracted ground wars.

More generally, President Trump should ask Congress to revise the War Powers Resolution. White House lawyers should study the recommendations of the 2008 National War Powers Commission, co-chaired by former Secretaries of State James Baker and Warren Christopher, which called the resolution “impractical and ineffective.” The Commission recommended the resolution be repealed and replaced with a mandatory congressional consultation process. Senators John McCain and Tim Kaine introduced legislation in 2014 to implement the commission’s recommendations.

With respect to international law, although other governments are unlikely to agree to amend the UN Charter or the 1949 Geneva Conventions, the Trump administration should still try to work with them to develop appropriate principles for use of force against, and detention of, members of non-state terrorist groups, where existing laws have gaps. And while President Trump seems less likely to authorize the use of U.S. military force for humanitarian purposes, his administration should still discuss with U.S. allies the rules for humanitarian intervention.

Some conservatives may resist complying with international rules that restrict U.S. freedom of action, but the Trump administration will find that the United States is most effective in its international actions when it follows the law. If the United States ignores or skirts international law regarding use of force, it makes it difficult for us to criticize other countries—like Russia or China—if they do the same. It also makes our allies who respect international law and share our values less likely to cooperate with us on intelligence, law enforcement, diplomatic, and military matters. To the extent that domestic and international law are outdated, President Trump should do what his predecessor was unable or unwilling to do: persuade Congress and our allies to modernize them to address contemporary problems.