As the U.S. and Israel’s war against Iran reaches 100 days, questions about presidential war powers are back in the spotlight. Congress has not officially declared war since 1944-era precedent in 1942, yet presidents have repeatedly launched major operations w
When the 100-day mark arrived for the United States’ and Israel’s war against Iran, the argument didn’t start on a battlefield. It started in Congress—over whether the president needed authorization to launch offensive forces in the first place.
Operation Epic Fury was launched without congressional authorization, lawmakers argue is required under the Constitution. On June 3. the House of Representatives passed a War Powers resolution that. if passed by the Senate. would require the removal of all offensive forces within 30 days of its passage. In May, the Senate advanced its own resolution, which hasn’t reached a final vote. Bringing the House resolution to a Senate vote would require 60 votes in the Senate. If it clears that threshold. President Donald Trump would then be able to veto it. with any override requiring a two-thirds vote in both houses.
The pushback is sharpened by Trump’s earlier claim that a ceasefire with Iran meant hostilities were “terminated,” making congressional approval unnecessary. Since then, the U.S. has carried out further strikes against Iran, which government officials labeled “self-defense” strikes.
Congress hasn’t officially declared war since June 4. 1942. when it declared war on Bulgaria. Hungary. and Romania during World War II. Since then. Congress has usually approved the use of force through “Authorization for Use of Military Force.” While not an official declaration of war. such authorizations allow the military to engage in targeted objectives. according to the Library of Congress.
Still, there have been plenty of times in American history when presidents ordered large-scale military operations without direct congressional approval. Some of those moves were met with legal challenges. while others escaped sustained scrutiny—often because public and congressional support made confrontation politically risky.
Andrew Wiest, a professor of military history at the University of Southern Mississippi, described the modern pattern as a concession of war powers from Congress to the executive branch since WWII.
“Since 1946, Congress has relinquished this constitutional authority and granted it to the president, probably much to the founders’ chagrin,” Wiest said. “The founders were extremely wary of a president with too much military authority.”
The current fight echoes through earlier operations—11 notable examples of U.S. military action carried out without direct congressional approval.
A war that began with a treaty
In 1899, in the Philippine-American War, President William McKinley never sought a formal declaration of war or authorization from Congress. After the Spanish-American War, the Philippine Islands were ceded to the U.S. under the Treaty of Paris in 1898. Filipino revolutionary fighters declared independence and resisted American attempts to acquire the islands.
McKinley interpreted the newly ratified Treaty of Paris as an effective approval of force from lawmakers. The war was controversial in Congress, with anti-imperialists arguing the annexation of the Philippines was illegal, according to the House of Representatives.
The war lasted over three years, from 1899 to 1902. American deaths totaled 4,200. About 20,000 Filipino fighters were killed, while up to 200,000 Filipino civilians died of disease, famine, and violence, per the Department of State.
A “police action” without congressional backing
In 1950, North Korean forces invaded South Korea after the U.S. and the Soviet Union divided Korea into two countries following WWII. The United Nations Security Council soon directed member nations to assist South Korea, prompting U.S. involvement.
President Harry Truman did not seek any form of approval from Congress, instead labeling the U.S. efforts a “police action” under the auspices of the UN. Some members of Congress disputed that framing. Republican Senator Robert Taft said the lack of congressional approval was “a complete usurpation by the president of authority to use the armed forces of this country. ” per the Brennan Center.
Wiest said the international character of the effort overshadowed the lack of congressional approval.
“At the time, the UN was young, robust, and something new,” Wiest said. “With a UN resolution to defend South Korea, what more top cover do you need?”
The Korean War lasted three years and resulted in the deaths of 37,000 American soldiers, according to the Department of Defense. As many as 5 million people died in total from the conflict, many of them civilians.
A Gulf of Tonkin approval later pulled—yet force continued
In Vietnam, Congress passed the Gulf of Tonkin Resolution in August 1964, giving President Lyndon Johnson authority to use military force in Vietnam and surrounding countries. But as opposition at home grew, questions emerged about Johnson’s continued war powers.
Two years after Richard Nixon assumed office, Congress repealed the resolution, leaving no law on the books authorizing U.S. military force in Southeast Asia. Even as Nixon reduced the number of deployed U.S. troops starting in 1969, bombing campaigns continued until the end of the war.
A federal appeals court later declared the war a political issue and did not rule on the legality of Nixon’s continued bombing, The New York Times reported. In total, 58,220 Americans died as a result of the war, per the National Archives.
Bombing secret supply routes—then Congress pushes back
President Richard Nixon also conducted bombing campaigns in Cambodia that began in 1969 and continued after the repeal of the Gulf of Tonkin resolution. The operation aimed to disrupt supply routes along the Ho Chi Minh trail and to target suspected communist hubs. It began in secret without Congress being informed.
In response, Congress passed the War Powers Resolution of 1973 to limit the president’s power in conducting military operations. Nixon vetoed it, but Congress overrode the veto with a two-thirds majority.
Wiest called the successful war-powers challenge a rare moment where Congress reclaimed its war powers.
“Partisanship and politics is part of it,” Wiest said. “No congressman can be seen as being against the troops. In my view, there’s no more risky electoral thing to do.”
From 1969 to 1973, the U.S. dropped 540,000 tons of bombs on Cambodia. Estimates for civilians killed range from 150,000 to 500,000, per PBS Frontline.
Grenada: an invasion ordered without approval
In 1983, a coup in Grenada resulted in the execution of Grenada’s leader, Maurice Bishop. The U.S. said its move was intended to protect hundreds of medical students and restore order after the government’s overthrow, and it invaded with help from Caribbean allies.
The invasion, ordered by President Ronald Reagan, was carried out without congressional approval. Congress then applied the War Powers Resolution, forcing withdrawal of U.S. troops within 60 days, The New York Times reported.
The campaign lasted eight days, killing 19 U.S. soldiers and 24 Grenadian civilians, per Army University Press.
Panama: Operation Just Cause without congressional approval
In 1989, the U.S. invaded Panama under the codename Operation Just Cause. The intention was to overthrow Panama’s leader, Manuel Noriega, who was indicted under U.S. law for drug trafficking. Other reasons cited for the operation included protecting Americans in Panama, defending democracy, and protecting the Panama Canal treaties.
The State Department said the actions were carried out with the consent of Panama’s legitimate government, sworn in before the invasion.
President George H.W. Bush, like Reagan before him, did not seek congressional approval beforehand. Still, the invasion had strong public and congressional support, subduing potential war-powers challenges.
The invasion was swift. Noriega was captured quickly and tried in the U.S., later convicted and sentenced to 40 years in prison, eventually serving 17 years in the U.S.
Overall, 23 U.S. soldiers were killed in the operation. An internal U.S. Army memo estimated Panamanian deaths at around 1,000, per Politico.
Yugoslavia: strikes, a failed authorization attempt, and a lawsuit dismissed
During the Kosovo War, NATO forces led by the U.S. initiated a bombing campaign in Yugoslavia against the Yugoslav Army.
NATO said the strikes were intended to stop “ethnic cleansing” of Kosovar Albanians by Yugoslav forces and to pressure those forces to leave Kosovo. Congress had voted in March of 1999 to send U.S. peacekeeping troops to NATO before the bombing began. but a later House measure authorizing the strikes failed in a tie vote.
After President Bill Clinton continued the bombing campaign, a war powers lawsuit was filed by 31 members of the House. A judge dismissed it on the grounds that “a clear impasse between the executive and legislative branches” was absent, CBS News reported.
Wiest compared the legal logic to earlier patterns—saying the internationalism after the end of the Cold War provided cover for the operation’s legality.
“It was a period of early optimism in the wake of a world-changing event, so that optimism, with the top cover of the UN or NATO, just overwhelmed any American constitutional need to declare war,” he said.
The strikes killed over 1,000 Yugoslav combatants and claimed the lives of roughly 500 civilians, per Human Rights Watch.
Libya: UN authorization, but no congressional sign-off—then court fights
In 2011, as part of a NATO intervention in Libya, U.S. forces participated in strikes during the Libyan Civil War. After Libyan leader Muammar Gaddafi attacked civilians, the United Nations Security Council adopted Resolution 1973 on March 17, 2011, authorizing military action in Libya.
President Barack Obama did not seek congressional approval, leading to criticism from Congress. Ten House members filed a lawsuit to block further military action, NPR reported.
A federal judge, Reggie Walton, later dismissed the case. He said lawmakers already had the legislative means to challenge the operation in Congress. Walton also said, “…the Court finds it frustrating to expend time and effort adjudicating the relitigation of settled questions of law.”
The Obama administration used the UN Security Council resolution to justify the action and argued the operation was limited and within the scope of the War Powers Resolution.
Yemen: strikes over shipping, with both Biden and Trump taking action
The U.S. struck Houthi targets in Yemen after the group began targeting commercial ships in 2023 in response to Israel’s invasion of the Gaza Strip.
Both the Biden and Trump administrations conducted strikes against the Houthis without seeking congressional approval. The most recent strikes in 2025, conducted by the Trump administration, killed at least 224 civilians, per the Middle East monitoring group Airwars.
Wiest said air and ground operations have been treated differently under war powers. He argued air power has offered more leeway.
“The use of air power has almost been a kind of national ‘Get Out of Jail Free’ card when it comes to opening these types of conflicts,” he said.
Iran nuclear sites: Operation Midnight Hammer without congressional approval
In 2025, the Trump administration carried out strikes on Iran’s nuclear facilities without congressional approval under the codename Operation Midnight Hammer. Trump argued the strikes were a necessary measure to prevent Iran from developing a nuclear weapon.
While the strikes had broad support among Republican lawmakers, Democrats and Republican Thomas Massie criticized the operation’s lack of authorization from Congress, NPR reported.
Venezuela: law-enforcement framing, war powers resolution blocked
On January 3, 2026, the Trump administration conducted surprise strikes on Venezuela that deposed President Nicolás Maduro. Maduro was captured and brought to the U.S., where he faces narco-terrorism and other drug charges. The former Venezuelan leader pleaded not guilty.
The administration justified the strikes as “law-enforcement operations” targeting what it called Maduro’s “narco-terrorist organization.” The strikes resulted in about 75 deaths. including two civilians and 32 Cuban special forces. per the Center for Strategic & International Studies. Seven American troops were injured.
Critics in Congress questioned the legality of the intervention. A war powers resolution was brought to the Senate floor for a vote but was blocked by the Republican-led majority.
Editor’s note: This story was originally published in March 2026 and was most recently updated in June 2026.
The through-line from these episodes is stark: presidents have repeatedly found ways to act first—often backed by legal interpretations, treaty or UN/NATO cover, or political momentum—while Congress has come into the picture later, when the question shifts from authorization to accountability.
War Powers Resolution Congress presidential war powers Operation Epic Fury Iran strikes Donald Trump Andrew Wiest military operations without authorization Philippine-American War Korean War Vietnam War Cambodia bombing invasion of Grenada Operation Just Cause NATO bombing of Yugoslavia Libya 2011 intervention Yemen strikes Operation Midnight Hammer Venezuela raid 2026