Congress has not formally declared war since World War II. Here’s how presidential war powers have evolved since then

During Donald Trump’s second term, Congress has several times discussed his military authority, first in Latin America and now in the Middle East.

Watch live: The House of Representatives is expected to vote on a resolution regarding war powers against Iran

The latest test in the GOP-controlled House will come on Thursday after the Senate voted against a Democratic measure to limit Trump, at least in theory, in the US-Israel war against Iran.

Like many of his predecessors, Trump claims broad, even unlimited, authority over US forces. He approved boat strikes near Venezuela, imposed a naval blockade, and authorized a military operation to arrest and remove its leader Nicolas Maduro – all arguable acts of war under international law. He made noise about additional action in Greenland and Latin America, before launching a large-scale bombing campaign in Iran.

Under the Constitution, the military reports to the president. But the document gives oversight roles to Congress. Trump says he will not sign anything that limits his options — evidence to some experts that control of the civilian-led military has deviated from its original design.

“The Constitution grants war powers to two different branches of government,” said military historian Peter Mansour, a professor at Ohio State University and a retired U.S. Army colonel. “The pendulum has swung toward executive power,” he lamented, arguing that “the framers of the Constitution intended Congress to be the stronger authority.”

He watches: Johnson says limiting Trump’s power with the War Powers Act is “dangerous.”

Here’s a look at what the Constitution says and how America’s war powers played out.

What does the Constitution say about war powers?

Article I, created by Congress, states that lawmakers “shall have the power… to declare war.” Article II, which created the presidency, makes the chief executive “Commander-in-Chief of the Army and Navy.” The Constitution also gives Congress authority over military budgets.

Congress has not officially declared a state of war since World War II. However, since 1945, American service members have fought and died in large-scale conflicts in Korea, Vietnam, Iraq, and Afghanistan, among other places.

On Maduro’s mission, an Army pilot was wounded, prompting Trump to award him the Medal of Honor — a recognition legally limited to actions taken when fighting a foreign enemy. As of Wednesday, six US service members have died in the Iran war.

During last month’s Senate debate on Venezuela, Sen. Rand Paul, R-Ky., mocked “an elaborate song and dance” and said it was “ridiculous” to suggest that Trump’s actions were anything other than waging war.

Sen. Tim Kaine, the Virginia Democrat who sponsored the war powers resolutions in Venezuela and Iran, said the latest version — which failed by a 47-53 vote — would prevent a presidential “final walk-through” on the Constitution.

Declarations of War: 11 – But no declaration has occurred since World War II

Congress declared war on 11 countries across five wars. Three proclamations were issued in the nineteenth century, two during World War I and six during World War II. Each time, the president formally asked Congress to act, citing some specific attack on the United States or other national interest.

Indeed, President James K. Polk even called for the Mexican War, which was primarily aimed at expanding American territory.

During the same period, Congress voted several times to authorize the use of force without declaring war. Early measures typically concerned specific maritime actions defending U.S. commercial interests. Congress first took this route in 1798; It has become a road map for the post-World War II era.

The Korean War marked a shift toward presidential power

President Harry Truman won World War II under proclamations issued while Franklin Roosevelt was president. Then, in 1950, the fledgling United Nations voted in favor of action in Korea and asked member states for help.

Citing the United Nations, Truman involved American forces in so-called “police work” without obtaining the approval of legislators. Later that year, Congress approved the Defense Production Act to mobilize America’s wartime capabilities. It was an endorsement of the Truman decision, and the law remains a potential tool for the Pentagon.

Vietnam demonstrated the extent of the power of Congress and the presidency

Presidents from Dwight Eisenhower to Gerald Ford oversaw what history remembers as the “Vietnam War,” though it was more often called the “Vietnam Conflict” as U.S. administrations expanded operations in Southeast Asia.

Lyndon Johnson convinced Congress to pass the Gulf of Tonkin Resolution in 1964 and used that to accelerate American intervention.

As the number of deaths in the United States rose, the war became unpopular, but Johnson – and then Richard Nixon – enjoyed broad power from lawmakers. “Congress approves and supports the determination of the President, as Commander-in-Chief, to repel any armed attack against the forces of the United States and prevent further aggression,” the 1964 resolution said.

Congress repealed the measure in 1971, but Nixon did not withdraw.

Mansour said that war declarations do not only determine the beginning of the war. It also effectively requires a formal end – which triggers the Senate’s role in ratifying peace treaties. Mansour said that bypassing these legal barriers is “how you enter into these eternal wars.”

Congress responds with the War Powers Act

In 1973, as the United States was moving out of Vietnam, Congress passed the War Powers Resolution, which intended to impose guardrails on presidents by requiring certain communication with lawmakers and allowing Congress to hold votes to set parameters for military action. This was the legislative impetus this year for the failed Venezuela resolutions and the Iran-related resolutions.

In 2020, the Democratic-controlled House of Representatives narrowly adopted a measure aimed at curtailing Trump’s powers against Iran at that point. But in practice, the War Powers Resolution was not a functional check on executive power.

After Vietnam, presidents assert their role as commander-in-chief

Ronald Reagan sent troops to Lebanon in 1982 as part of a multinational peacekeeping force. He did not cite the War Powers Resolution when notifying Congress and did not approve congressional authorization until 1983—after service members had already died.

In 1990, George H. W. Bush notified Congress under the War Powers Resolution that he had sent troops to the Middle East after Iraq’s invasion of Kuwait. Bush asked Congress for “support” – rather than “authorisation” – only after obtaining UN support for action by an international coalition led by US forces. Congress authorized the use of force in January 1991.

Bill Clinton deployed US troops several times – to Somalia, Haiti, Rwanda, Bosnia and Herzegovina, Kosovo, and Iraq. He asked Congress for appropriations but not explicit mandates. When some lawmakers pressed Clinton to approve strikes in Iraq in 1998, Clinton asserted his interpretation of presidential power — in contrast to Trump’s arguments.

Bush describes 9/11 as an act of war, but never seeks to declare it

George W. Bush quickly mobilized the armed forces after the terrorist attacks of September 11, 2001. He quickly consulted with Congress, which led to a joint resolution authorizing sweeping action. It was unique because no specific country was targeted and it initially focused on Al Qaeda. Congress almost unanimously supported the measure but required reporting every 60 days.

Mansour, the military historian, noted that Bush used voting to carry out counter-terrorism efforts anywhere in the world. Bush returned to Congress in 2002 and told the leaders that he wanted to obtain authorization to act against Iraq.

What Congress passed to Bush had no effective expiration date. His successor, Barack Obama, inherited forces in Iraq and did not initially withdraw them. Afghanistan lasted through Obama’s terms, Trump’s first presidency, and even Joe Biden’s term.

Biden has withdrawn US troops from Afghanistan after it became the longest US war – never declared – in the country’s history.