VP Nixon decided to throw away the peace treaty in Vietnam, and start the Vietnam War, he committed the USA to complete military backing. He thought in terms of the Korean War, and spoke of tanks and division strength movements, but he was willing to have the USA in the war that he had just started.
That being said, JFK and LBJ could have just walked away from the war Nixon started. They did not have to commit US troops. That basically concedes your point, but the war started under Eisenhower(Nixon), and the initial promises of unlimited military forces were made by Nixon.
It is interesting that Nixon wanted control over Northeast Asia (Korea), and Europe for the Eisenhower Administration. Instead, he was given the Caribbean(Cuba), and Southeast Asia(Vietnam), both of which collapsed under his watch.
In one election, the popular vote is unimportant. In multiple elections, it shows the direction the people are going. If a party cannot win the popular vote, they may win an election or two, but they are headed for irrelevant. To make it worse, it usually is part of a trend.
Republicans are locked into a minority demographic that is shrinking as a percent of the voting population. They almost lost Texas now several times in a row, and have lost Georgia... When Texas and Georgia are battleground states, they are in trouble.
