ALSO SEE: Dozens of Democrats Call for Trump's Removal After His Iran Threats

President Donald Trump started Tuesday threatening that Iranian “civilization will die.” He ended the day proclaiming a two-week cease fire and a path toward an end to the war — easing oil prices and sending market futures higher.

But he still faces challenges on Capitol Hill, where Democrats ended up more eager than ever to rein Trump in and Republicans were ambivalent at best about Trump’s saber-rattling approach.

Incensed by Trump’s breathtaking ultimatum, House Democrats intend to call up a war powers resolution as soon as lawmakers return next week, Minority Leader Hakeem Jeffries said in a CNN interview Tuesday night.

Jeffries has shored up support among his own ranks, and Democrats are working to convince at least two Republicans to join them in curbing Trump’s authority in Iran.

Most Republicans, including Speaker Mike Johnson and Senate Majority Leader John Thune, kept quiet on his threat to attack 93 million Iranians. Many assumed — or hoped — Trump’s bluster was a negotiating ploy, and their restraint was ultimately rewarded.

But a few aired concerns with the president’s rhetoric, and they will soon be faced with deciding whether to put their votes where their mouth is.

“I do not support the destruction of a ‘whole civilization’,” Rep. Nathaniel Moran said on X. “That is not who we are, and it is not consistent with the principles that have long guided America.”

Johnson and Thune will argue that Trump needs complete flexibility and maximum leverage as he pursues negotiations with the Iranian regime. The announcement that oil and other commodities could soon be flowing through the Strait of Hormuz could help them make the sale to GOP members nervous about rising gas prices and falling poll numbers.

As for Democrats, Trump’s U-turn might have taken the bite out of the renewed calls from some members for impeachment and removal under the 25th Amendment. But party leaders are bullish about putting Republican lawmakers on the record as Day 40 of the war draws closer.

A war powers vote might only be a prelude to the real litmus test for Congress: a potential vote on defense funding, with Trump himself floating a $350 billion request, that could come even closer to the midterms.

What else we’re watching today: Trump meets with NATO’s Secretary General Mark Rutte at the White House. While Trump has lashed out at alliance members for withholding support in the early weeks of the war, we’ll see if key congressional voices take the opportunity to speak up on NATO’s behalf.

“Close consultation with allies doesn’t constrain our action to secure our interests; it enhances it,” Sen. Mitch McConnell said in a statement.