Donald Trump has eight days before he will be forced to make up his mind on Iran.
He wants to end the unpopular war, but claimed on Thursday he was under “no time pressure” to do so.
In fact, the US president is bound by the 1973 War Powers Resolution, which limits his ability to wage war without congressional approval to 60 days.
That deadline passes on May 1, 60 days after his formal notification of the war to Congress on March 2.
It will compel him to choose one of four options – seek congressional authorisation to continue the war, start winding down US involvement, buy some breathing space or ignore the law.
Some Democrats say the war is illegal and dismiss Mr Trump’s justification that it was necessary for the US national interest and “collective self-defence of regional allies, including Israel”.
But several Senate Republicans have made it clear that they will not support a war without congressional approval past the 60-day mark.
Brian Mast, the representative for Florida and chairman of the House foreign affairs committee, warned that the vote could be different next time after the last of five Democratic efforts to stop the offensive failed.
End the war
Ending the war is easier said than done. A second round of peace talks in Pakistan did not take place after Iran refused to confirm that it would attend.
Mr Trump has extended the two-week ceasefire indefinitely as he seeks a way out of the costly conflict.
He refuses to end his blockade of Iranian ports, which he proactively declared during the ceasefire. Tehran will not consider peace while the naval blockade continues and trust in the US is extremely low.
Iran’s clerical state is not on the verge of collapsing and will not surrender, said Danny Citrinowicz, a former Israeli intelligence expert on Iran, now at Tel Aviv University’s Institute for National Security Studies and the Washington-based Atlantic Council.
Mr Citrinowicz said the president “does not want escalation”, adding: “I am not saying there is not going to be one, but he is trying to really exhaust any political option.
“I think Trump is fed up with this war and more than that he understands, despite what he is saying, that the price is only going to intensify.”
Mr Trump will need to claim some sort of “win,” whether that is an iron-clad commitment from Iran not to enrich uranium, or to remove its stockpile completely.
But American voters are now being forced to pay more at the pumps just months before congressional elections.
Challenged on his timeline on Thursday, Mr Trump said: “People say I want to get it over because of the midterms. Not true.” He added that the administration wanted to “get a good deal for the American people”.
Extend the deadline
The war powers law provides for a single 30-day extension of the campaign without congressional approval if certain conditions are met.
The president must certify in writing that more time is needed to safely withdraw US forces. Importantly, this does not give permission for him to continue waging an offensive campaign.
Get congressional approval
Congress can authorise Mr Trump to use military force. This has been the main way it has approved campaigns since the Second World War, which was the last time the US formally declared war. US legislators last voted in favour of using military force in 2002, against Iraq.
Republicans have united to defeat Democrats’ efforts to stop the war. They are more divided over giving Mr Trump permission to continue it. Some of the president’s once most enthusiastic supporters have turned on him for embracing “forever wars”, and midterms are looming.
There will be a price to pay for congressional backing.
Lisa Murkowski, the Republican senator for Alaska, is working with a group of other senators on a formal authorisation. She said her goal was to reassert congressional authority and secure commitments over the objectives, costs and timelines for the war.
Ignore the deadline
Democrat and Republican presidents have argued that the war powers law is unconstitutional because the US Constitution gives sweeping authority to the commander-in-chief.
Barack Obama continued a military campaign in Libya past the 60-day deadline in 2011, weathering a backlash from both parties. He said the law did not apply because “US operations do not involve sustained fighting or active exchanges of fire with hostile forces, nor do they involve US ground troops”.
Mr Trump could make the same argument about his war in Iran.
In his first term, he vetoed a bipartisan resolution passed to end US involvement in Saudi Arabia’s civil war in Yemen. He said the measure was an “unnecessary, dangerous attempt to weaken my constitutional authorities”.
Ignoring the deadline, though, could cause problems in the Republican Party. Some senators have made it a red line after giving Mr Trump significant latitude to wage the unpopular war without formal oversight or congressional involvement.