Johnson did not know that he could get a declaration; the public might not be prepared to go to war. For this reason, rather than ask for a declaration, he used all the prior precedents to simply go to war without a declaration. In my view, that was the moment the declaration of war as a constitutional imperative collapsed. And in my view, so did the Johnson presidency. In hindsight, he needed a declaration badly, and if he could not get it, Vietnam would have been lost, and so may have been his presidency. Since Vietnam was lost anyway from lack of public consensus, his decision was a mistake. But it set the stage for everything that came after — war by resolution rather than by formal constitutional process.