Would it, though?
If they take out Trump or (more likely) a close relative or friend as an act of revenge, I think it’s extremely questionable whether a declaration of war would be voted through. There would be a really strong argument that he’d brought it on himself.
However a mass casualty attack in the Gulf, against an embassy or an attack against civilians on the continental US would almost guarantee it; it would unify the US whereas an attack on Trump / an associate would probably divide it.