The US is still not in a hot war with Iran. The lines of war have been blurred since nations stopped formally declaring war on each other, and this was a precision strike, not a declaration. Whether you think it was the right thing to do or not - and as much as Trump appears to do Israels bidding - it could still work out in Trumps favour if Iran back down - since it would effectively be a show of strength preventing a larger scale conflict. Hard to tell what Iran will do, though, since they may have been pushed too far, and this could blow up on Trump's face.