...I believe you are correct....I am no historian, but if my memory serves me correctly, LBJ inherited that war in Southeast Asia from JFK that he really did not wholeheartedly support, but he was fearful of appearing to be “soft on communism” to quote the expression of the day.... as they say, the rest is bloody, wasteful and futile history....
LBJ once said that he had to escalate in Vietnam because he didn’t want to be the first American president to lose a war. So his ego took precedence over American lives and American treasure.
The Founders foresaw such a possibility. So they gave Congress - and not the president - the power to declare war. But since WWII everybody involved has casually ignored that part of the Constitution.