Photo: Mark Wilson/Getty Images

On Thursday night, President Trump approved strikes on Iran in retaliation for a $130 million American surveillance drone that was shot down in the Gulf of Oman. Ultimately, he backed off the decision. Military aircraft had taken off and ships were in position when the order to stand down was issued; no missiles had been fired, according to an official who spoke with the New York Times.

On Friday morning, Trump tweeted that he had called off the strikes because they were “not proportionate” to Iran’s provocations; in his telling, he was informed by a general that they would cause 150 deaths.

....On Monday they shot down an unmanned drone flying in International Waters. We were cocked & loaded to retaliate last night on 3 different sights when I asked, how many will die. 150 people, sir, was the answer from a General. 10 minutes before the strike I stopped it, not.... — Donald J. Trump (@realDonaldTrump) June 21, 2019

....proportionate to shooting down an unmanned drone. I am in no hurry, our Military is rebuilt, new, and ready to go, by far the best in the world. Sanctions are biting & more added last night. Iran can NEVER have Nuclear Weapons, not against the USA, and not against the WORLD! — Donald J. Trump (@realDonaldTrump) June 21, 2019

As late as 7 p.m., military officials were expecting a strike after serious debate among the president’s national-security advisors and congressional leaders. Trump had initially approved attacks on Iranian targets including radar and missile batteries before the attack was called off.

The strike was timed to occur just before dawn in Iran in an effort to avoid casualties. On Thursday, the president claimed that the downed drone was flying over international waters in the Gulf of Oman, though Iran released GPS coordinates showing that the drone was eight miles off its coast, well within territorial waters.

When congressional Democrats were briefed, they immediately urged de-escalation. “This is a dangerous situation,” Nancy Pelosi said. “We are dealing with a country that is a bad actor in the region. We have no illusions about Iran in terms of their ballistic-missile transfers, about who they support in the region and the rest.” Top voices in the Trump administration — including Secretary of State Mike Pompeo, national security adviser John Bolton, and CIA director Gina Haspel — have lobbied for the president to take military action. But Trump has stated in private and public that he doesn’t want to engage in conflict. On Thursday, he said that someone “loose and stupid” was responsible for shooting down the drone, as if to avoid accusing leadership in Tehran for the action.

The Revolutionary Guard’s top commander, Maj. Gen. Hossein Salami, called the downing of the 16-ton drone “a clear message to America.”

“Our borders are Iran’s red line, and we will react strongly against any aggression,” Salami said on state television. “Iran is not seeking war with any country, but we are fully prepared to defend Iran.”

In Washington, Chuck Schumer warned that “these conflicts have a way of escalating,” adding that “the president may not intend to go to war here, but we’re worried that he and the administration may bumble into a war,” he said. “One of the best ways to avoid bumbling into war, a war that nobody wants, is to have a robust open debate and for Congress to have a real say. We learned that lesson in the run-up to Iraq.”

This post has been updated.