Why are we at war with Iran? The Trump administration has so far botched its rationale for Operation Epic Fury.

For several days after the initial strikes two Saturdays ago, Trump officials’ explanations were vague. Then, last Tuesday, Secretary of State Marco Rubio said: “We knew that there ​was going to be an Israeli action. We knew that that would precipitate an attack against American forces, and we knew that if we ​didn’t preemptively go after them before they ​launched those attacks, we would suffer higher casualties.”

These comments triggered an almighty political argument—and the administration quickly tried to walk them back. But the bigger problem was legal. Though the Trump administration has claimed that Iran posed an imminent threat, it has not publicly provided detailed evidence for that claim; Rubio’s comments remain the most concrete explanation offered so far. If what Rubio said was true, and Israel did force America’s hand, the administration is relying on a shaky interpretation of the Constitution to wage war.