The War Powers Resolution, passed after the Vietnam War, was designed to prevent presidents from leading the United States into long, undeclared wars. It requires the president to notify Congress within 48 hours of sending troops into “hostilities” and gives Congress 60 days to approve the action. If lawmakers do not give approval, the president is supposed to end the military operation, with a possible 30-day extension to allow for a safe withdrawal.

In the current conflict with Iran, Donald Trump did not ask Congress for authorization. The 60-day deadline is approaching, but even its exact timing is disputed. Some lawmakers argue the clock began when fighting started, while others say it began when Congress was formally notified. There is also disagreement over whether a ceasefire pauses or resets the timeline.

In reality, the law has rarely worked as intended. Since its passage in 1973, no president has fully accepted its limits. Richard Nixon vetoed it, arguing it restricted executive power, though Congress overrode him. Later presidents, including Ronald Reagan, Bill Clinton, and Barack Obama, found ways to continue military operations without clear approval, often by narrowly defining what counts as “hostilities” or by relying on funding already approved by Congress.

Courts have generally refused to step in, saying disputes over war powers are political questions better handled by elected officials. At the same time, Congress is often hesitant to challenge a president during a conflict, partly for political reasons and partly out of concern for national unity.

This situation highlights an ongoing tension in the US system: the Constitution gives Congress the power to declare war, but modern presidents frequently take the lead in military decisions. Whether Trump follows the law or ignores it could influence how much authority future presidents claim when using military force without congressional approval.