Explained: Can Trump go to war in Iran without approval from US Congress?

Donald Trump's decision to strike Iran's nuclear sites reignites debate over the 1973 War Powers Resolution and raises questions about presidential authority and potential impeachment

With US President Donald Trump ordering air strikes on three nuclear facilities in Iran—Fordow, Natanz and Isfahan—debate has intensified over the limits of presidential war powers. The strikes, the boldest US intervention yet in the Iran-Israel conflict, have not been accompanied by a formal declaration of war—prompting legal and political scrutiny in Washington.

 

Could Trump be impeached for bypassing Congress? And what role does the War Powers Resolution of 1973 play in curbing presidential overreach?

 

Why War Powers Resolution was introduced in 1973

 

The War Powers Resolution (WPR), also known as the War Powers Act, was passed in 1973 in the aftermath of the Vietnam War—a prolonged conflict that saw major US involvement without a formal declaration of war.

 

The resolution was designed to prevent the President from unilaterally engaging American forces in hostilities without Congressional oversight. It sought to restore the balance of power by:

 

• Requiring the President to notify Congress within 48 hours of deploying troops
• Mandating the withdrawal of troops within 60 days unless Congress approves their continued presence
• Allowing a 30-day grace period for safe withdrawal

 

Although intended as a check on executive power, the WPR has rarely been enforced effectively, with successive Presidents—including Trump—often sidestepping or challenging its authority. 

 

What US Constitution says about declaring war

 

The US Constitution clearly assigns Congress the sole authority to declare war (Article I, Section 8), while naming the President as Commander-in-Chief of the armed forces (Article II, Section 2).

 

This division was meant to ensure that decisions to enter large-scale military conflicts reflect democratic consensus. In practice, however, modern Presidents have increasingly relied on executive authority to conduct military operations without formal war declarations.

 

Presidential precedents and Trump’s Iran strike

 

The US has not declared war since World War II, but has engaged in several major conflicts—Korea, Vietnam, Iraq, Afghanistan—without Congressional war declarations. Trump’s own administration has previously carried out strikes in Syria (2017 and 2018) without Congressional approval.

 

In the case of Iran, Trump has framed the air strikes as necessary to prevent Tehran from acquiring nuclear weapons. US officials say the attacks were “limited, targeted, and in coordination with Israel”—and not indicative of a wider war effort.

 

Could Trump be impeached over war in Iran?

 

In theory, yes. If Congress believes the President has violated the Constitution or laws such as the War Powers Resolution, it can initiate impeachment proceedings. However, such action would depend heavily on political will.

 

Past presidents—including Barack Obama, George W Bush and Ronald Reagan—have conducted military operations without Congressional declarations of war, and none faced impeachment for it. Legal scholars remain divided over whether violation of the WPR alone constitutes a “high crime or misdemeanour” under the Constitution’s impeachment clause.

 

If Trump were to escalate the Iran conflict into a prolonged war without Congressional authorisation, and if it provokes significant domestic or international fallout, political calls for impeachment could grow louder. However, removal would still require a majority in the House and a two-thirds vote in the Senate—a high bar.

 

Amid mounting tensions with Iran, US lawmakers—both Democrats and some Republicans—have sought to pass resolutions limiting Trump’s ability to wage war. These efforts, while symbolically important, face procedural delays and are unlikely to override a presidential veto.

 

The constitutional ambiguity persists: while Congress alone can declare war, the President can, and often does, launch military action unilaterally—especially if framed as a defensive or time-sensitive measure.

 

What happens next?

 

As of now, Trump has insisted the US does not seek regime change in Iran and has framed the strikes as a “historic moment” to halt nuclear escalation. Iran, meanwhile, has vowed retaliation and hinted at broader regional consequences.

 

If the US becomes drawn into a longer, bloodier conflict, pressure may mount on Congress to act—whether through legislation, funding restrictions, or impeachment. Until then, the line between presidential authority and Congressional war power remains blurred.