Senator Todd Young (R-Indiana) joined Susan Collins, John Curtis, and Thom Tillis as the fourth Republican co-sponsor on 3 May 2026, with Murkowski confirming an 11 May filing target when the Senate returns from recess . The week of 11 May is three days from this update. The four-sponsor configuration is significant: it is the first Iran AUMF with a confirmed Republican quartet, bridging Murkowski's centrist independence with Tillis and Curtis's more orthodox Republican positions.

Murkowski's strategy is leverage, not legislation: by withholding the instrument she forces the White House to choose between delivering a strategy document and having an AUMF imposed on it by the Senate. The Murkowski-sets-four-11-May-AUMF-specs update documented four concrete criteria she attached to the bill, including declassified legal authorities, a phased drawdown timeline, and defined endstate conditions . The convergence of the WPR 60-day Deadline (passed 1 May) and the Section 1544(b) 30-day wind-down (operative cliff approximately 1 June) means her window of maximum leverage runs through the month.

Murkowski's AUMF is an Iran-specific Authorization for Use of Military Force draft from Senator Lisa Murkowski (R-Alaska). On 25 April 2026, Senators Collins and Tillis signalled support, with Tillis confirming it would 'settle the question of congressional backing'; the draft remained pre-committee with no markup date, six days before the 1 May War Powers Resolution Deadline. An AUMF authorises the President to use military force in a specific context. The War Powers Resolution requires such authorisation within 60 days of committing forces, or withdrawal. The Trump administration has not sought an AUMF, relying on pre-existing authorities; Murkowski's draft is the Senate's own initiative.

On 30 April, Murkowski set a concrete public Deadline: she would move the bill to the floor the week of 11 May unless the White House delivered a credible strategy document within seven days. The four-sponsor Coalition of Collins, Tillis, Curtis and Todd Young gives the instrument more Republican weight than any prior Iran war bill, though passage still requires a floor vote and committee referral.

Common Questions

What is Murkowski's Iran AUMF?

It is a draft Authorization for Use of Military Force specific to the Iran conflict, sponsored by Senator Murkowski with four Republican co-sponsors, targeting a Senate floor vote the week of 11 May 2026.Source:

Will the US Congress authorise the Iran war?

Uncertain. Murkowski's AUMF has three Republican supporters but no committee markup date, leaving no clear PATH to a vote before the 1 May War Powers Deadline. The Trump administration has not sought authorisation, relying on pre-existing authorities.Source: Lowdown

What happens if Congress does not authorise the Iran war by 1 May?

Under the War Powers Resolution, the President must withdraw forces within 60 days if Congress does not authorise the use of force. Day 60 falls on 1 May 2026. The Trump administration has not acknowledged a legal obligation to comply.

Who supports Murkowski's Iran AUMF?

As of 25 April 2026: Senators Susan Collins (Maine), Thom Tillis (North Carolina), and John Curtis (Utah) — all Republicans. The AUMF has not been formally introduced or referred to committee.Source: Lowdown

What is Murkowski's AUMF and when will it come to a vote?

Senator Lisa Murkowski drafted an Iran-specific Authorization for Use of Military Force. As of 30 April 2026, she set a Deadline of the week of 11 May for a floor vote unless the White House delivered a strategy document within seven days. Backers include Senators Collins, Tillis and Curtis.Source:

How is an AUMF different from the War Powers Resolution?

The War Powers Resolution requires congressional authorisation within 60 days or forces withdrawal. An AUMF grants the President specific authority to use force; Murkowski's draft would provide that authorisation for the Iran campaign, where the administration has relied on existing authorities rather than seeking fresh congressional approval.Source:

Why does the Trump administration oppose Murkowski's AUMF?

The White House has argued it is 'not at war' with Iran and that the WPR clock never started. Accepting an AUMF would legally codify the conflict, potentially constraining scope, duration and targeting rules in ways the executive branch wants to avoid.Source:

When will the Senate vote on the Iran AUMF?

Murkowski set a filing target of the week of 11 May 2026, three days from this update. The bill is pre-committee; passage requires referral, markup, and a floor vote.Source:

Why hasn't Trump requested an AUMF for Iran?

The administration has relied on pre-existing legal authorities. Murkowski's AUMF is the Senate's own initiative, framed around transparency and congressional oversight rather than a White House request.

Who are the co-sponsors of the Murkowski Iran AUMF?

Susan Collins (R-ME), Thom Tillis (R-NC), John Curtis (R-UT), and Todd Young (R-IN) are the four confirmed Republican co-sponsors as of 3 May 2026.Source:

Source Material

Authorization for Use of Military Force — Wikipedia Senator Lisa Murkowski — Congress.gov

How the World Sees Them

Iran (Tehran)

Prefers strategic ambiguity over a US AUMF that codifies hostilities in statute, potentially locking in the legal framework for a longer campaign.

US Senate Democrats / Schumer

Prefer the WPR-vote route that forces a direct withdrawal resolution; an AUMF grants formal war authorisation and risks being framed as congressional endorsement of the campaign.

US executive (Trump administration)

Prefers the 'not at war' reading that the WPR clock never started; a Murkowski AUMF that codifies hostilities legally would constrain scope and duration in ways the White House has consistently resisted.

US Senate Republicans (Collins/Tillis/Curtis)

Back the draft as a transparency mechanism rather than a constraint; the Collins WPR flip on 30 April lowered the political cost of AUMF support for persuadable Republicans.