Mr. Trump said he was “in no hurry” to retaliate. Such patience is wise. Perhaps he can use the additional time to sort out what is evidently a chaotic decision-making process. It’s alarming that a potentially lethal strike was averted with only 10 minutes to spare — and that, according to the president’s own account, he learned of the possible death toll only at the last minute. That’s very strange, and disturbing: Casualty estimates are routinely given to commanders and their civilian bosses early in the process of weighing military actions.

Also concerning is a report from The Times that the United States military cannot say for certain whether or not the drone violated Iranian sovereignty, as officials in Tehran have claimed. Trump administration officials had previously asserted that the drone was flying in international airspace. Clarity on such a pivotal fact about the incident should be a prerequisite for any further action.

If the trip to the brink of hostilities and back (at least for now) offers any lessons, it is that important decisions should not be made with minimal consultation and at the last possible moment.