What happened to the Democratic Party in 1968, 1972, 1980, 1984 and 1988 in those presidential defeats and in the case of 1980 when the not only lost the White House in a landslide, but lost the U.S. Senate and eleven seats at that, was that their Far-Left rose up in the late 1960s in response to the Vietnam War and to against American capitalism. As well and made the Democratic Party look way out of the mainstream than they actually were.
The Democratic Party lost five out of six presidential elections from 1968-88. They won in 1976, but Jimmy Carter ran against the Democratic establishment and to a certain extent the Far-Left. And went out-of-the-way to convince people who was a New Democrat and mainstream and someone who shared a lot of American values. Like hard work, honesty and so-forth who ran against Washington. But lost in 1980 partly because he wasn’t able to solve a lot of problems that he inherited. But also because the Far-Left didn’t like him and took their support somewhere else.
And because of the Far-Left rising in the Democratic Party, partisan right-wingers and Republicans were successfully able to paint all major Democrats especially national Democrats, as out of the American mainstream and somehow Un-American and big believers in big government. And anti-capitalist, anti-success, anti-military and other things and even though only a small faction of Democrats believe in these things. Republicans were able to paint most major Democrats as supporting these things.