The Myth of Liberal Fundamentalism

This is an excerpt from a 1989 report by the Progressive Policy Institute in response to the 1988 election. It's still relevant.

"The Myth of Liberal Fundamentalism: The oldest of these myths is that Democrats have lost presidential elections because they have strayed from traditional liberal orthodoxy. The perpetrators of this myth greet any deviation from liberal dogma, any attempt at innovation with the refrain "We don't need two Republican Parties." Liberal fundamentalists argue that the party's presidential problems stem from insufficiently liberal Democratic candidates who have failed to rally the party's faithful. The facts, however, do not sustain this allegation. Losing candidates Michael Dukakis and Walter Mondale were very successful, in fact in most instances more successful, than 1976 winner Jimmy Carter, in winning over the ideological (and racial) base of the Democratic Party. According to CBS/New York Times exit polls, Dukakis got 82 percent of the liberal vote and 89 percent of the black vote. This is better than Carter, who received 74 percent of the liberal vote and 83 percent of the black vote in 1976. Mondale's loss was so big that he did less well than Carter in most groups, but he still received 71 percent of the liberal vote and fully 91 percent of the black vote. The real problem is not insufficient liberalism on the part of the Democratic nominees; it is rather the fact that during the last two decades, most Democratic nominees have come to be seen as unacceptably liberal."

One of the authors of the report became a domestic policy adviser to Bill Clinton - Clinton used the lessons of this report to win in 1992 and 1996.
I keep hearing that "Clinton was a moderate and she lost." Here's the thing, most voters disagree. According to Pew, 58% of voters viewed Clinton as liberal on most or all issues. Only 28% viewed her as moderate. When it came to Trump, 44% viewed him as conservative and 40% viewed him as moderate.
Clinton lost for the same reason as Dukakis and Mondale - voters considered her to be too liberal.
In Nov 2008, 43% viewed Obama as Liberal, and 45% as Moderate. Compare those numbers to Clinton! Remember the 2008 primary. Obama positioned himself to the right of Clinton on a host of issues - especially health care.
It doesn't matter if polls show that voters agree with a candidate on specific issues. In the end what matters is how voters view the specific candidates.
In short, you win, when voters think you're more moderate...