As Mr. Trump last week weighed whether to use direct military force against Iran, a bipartisan contingent of lawmakers demanded that the president seek congressional approval before moving forward with any action.

Few people inside the administration knew the president was moving forward with plans for the attack, even late last week.

Although the operation achieved an impressive level of tactical success, with a swarm of warplanes penetrating Iran unchallenged following a long, undetected flight from Missouri, it will be far harder than the president has suggested to reliably evaluate the damage inflicted on Iran’s ability to manufacture a nuclear weapon.