President Trump, addressing the U.S., said, “Iran appears to be standing down, which is a good thing for all parties concerned and a very good thing for the world.” He announced sanctions and vowed not to let Iran obtain a nuclear weapon, but otherwise avoided new threats.

No Americans have been reported killed in the strike, prompting speculation that Iran may have calibrated an attack that avoided all-out war. Still, it is expected that Tehran’s proxy forces are not done yet.

Details: Iran attacked an air base in western Iraq that Mr. Trump visited in 2018, and another base near Erbil, in the north. Here’s what we know about them.

Mood in Washington: There was a collective exhaling in the Trump administration’s national security apparatus, and officials indicated they believed things had been contained, for now. In Congress, Speaker Nancy Pelosi plans to hold a vote Thursday to require Mr. Trump to cease all military action against Iran within 30 days unless approved by Congress.