I always thought Ford did a hell of a job considering the terribly weak position he inherited. He absolutely did the right thing pardoning Nixon. He had probably the worst Congress in our history to deal with (the 94th). He did veto spending increases -- many of which were overridden (on this score he did better than Reagan and Bush IMHO). He gave the OK to go after the Communists who grabbed the Mayaguez. The man was dealt the worst hand of any President and came out OK. He was prone to dumb ideas and gaffes (WIN Buttons and his asinine comment on Eastern Europe), but he was WAY down to Carter and after a VERY close win over Reagan he made up a lot of ground and almost upset Carter.
I don't think that anyone blamed Ford for Vietnam -- his hands were tied by Congress anyway. I do know people that voted for Carter solely because of the pardon. I don't care if Carter's win meant Reagan won in 1980 -- Carter was a total disaster across the board, and having him as President cost this country dearly. At least that goofball didn't get to appoint someone to SCOTUS!
I don't think so either, at least consciously. I think it was more subtle, primitive and psychological, than obvious and political. Whether its an ancient tribe or a modern civilization, the head of government, after a defeat, will loose his crown or office. It's human nature. The complicity of congress is the real factor in the loss of Vietnam, but, deep down, Congress is not a head that will roll all at once. To the electorate, Ford was head of state when the state lost a war. He must go, even if the successor is an unknown.