THE DEMOCRATIC DEBACLE last November came as no surprise to Senator Evan Bayh. The Indiana Democrat could see disaster looming and decided a year ago not to seek reelection. He began issuing warnings to fellow Democrats even before the passage of Obamacare, only to see them ignored. He told the Wall Street Journal his party’s liberals were “tone deaf” to the fact that they’d “overreached” in their agenda. “For those people,” he said, “it may take a political catastrophe of biblical proportions before they get it.” Now that the votes are in, Bayh still isn’t sure they will.

Bayh knows something about high-water political floods. As a 24-year-old law student he helped run his father’s 1980 Senate re-election and saw him go down to defeat under the Reagan landslide. In 1994, Bayh was governor of Indiana and thankful he wasn’t before the voters when they revolted against Bill Clinton. “Every 14 or 16 years we seem to have to relearn this lesson,” Mr. Bayh said. “I do have a sense of déjà vu, and the movie doesn’t have a happy ending.”

He isn’t the first observer to note the misfortune that befalls modern Democrats when they gain control of the presidency and both houses of Congress. Look at the record. In the last half century, Democrats have controlled the White House and both houses of Congress with big majorities four times: 1965-66, 1977-80, 1993-94, and 2009-10. As Henry Olsen of the American Enterprise Institute notes, each time “Democrats suffered landslide reversals in Congress within four years of obtaining their supermajorities. The only time they did not also then lose the presidency was in 1996, when the triangulator Bill Clinton was reelected. Is this a coincidence?”

One cannot easily blame the economy for those earlier defeats. The economy was humming in the 1960s, and it was steadily recovering during the early 1990s. Nor can one easily blame political consultants and clever Republican tricks. As anyone who follows advertising and politics knows, a campaign succeeds only if it communicates messages its audience wants to hear. The only thread that runs through all four of the landslide reversals is the fact that in each case liberals overreached and alienated independent voters enough that they turned to Republicans in protest.

Ronald Reagan understood this dynamic better than anyone. After Jimmy Carter won the White House, Reagan assembled a group of his former aides from his failed bid for the 1976 GOP nomination. The meeting took place in Los Angeles in 1977, and it soon turned into a pep talk by a man who was clearly hoping to keep the spirits of his troops up while he contemplated his own political future.

The Gipper’s basic message was that the GOP’s seemingly hopeless minority position would only be temporary if they learned from the Party’s mistakes and returned to first principles. He quoted from a ballad from the English poet John Dryden he had memorized as a youth: “I’m a little wounded, but I am not slain. I will lay me down for to bleed a while. Then I’ll rise and fight again.”

Conservatives, he said, should be of good cheer. He said Democrats tend to win the White House and big majorities in Congress when two things happen simultaneously: when “Republicans the voters have trusted don’t live up to conservative principles” and when Democratic candidates successfully campaign as moderates who can be trusted not to pursue a radical agenda in office.

Reagan’s case for optimism was his thesis that once in office Democrats find it impossible to govern as moderates even if they want to “because the unions and their congressional leadership won’t let them.” But governing as liberals meant Democrats undermined the trust voters placed in them. They also enacted policies that increased economic uncertainty and retarded job creation. “When liberalism fails, people notice. They may even protest,” Reagan told his aides, pointing to California’s nascent Proposition 13 tax revolt — the Tea Party of its day. “And it’s then they’ll listen to you again if you have a clear set of ideas based on sound principle.”

Aides such as Peter Hannaford who attended the meeting realized he was planning to run for president again, envisioning just such a scenario. The rest is history.

IN EARLY 1993, before he succumbed to Alzheimer’s, Reagan met with some of his appointees in New York City. The circumstances were remarkably similar to those of 16 years prior — Republicans had lost heavily in the last election due to scandal and economic miscalculations. Larry Kudlow, a Reagan budget official who is now a CNBC host, recalls that the Gipper reminded those at the meeting of what he’d said in 1977.

Bill Clinton had also campaigned as a moderate but was already governing as a liberal-and Reagan said it wouldn’t fly with voters. “He said the failure of liberalism would again present Republicans with an opportunity if they ran on a pro-growth, anti-tax agenda that reasserted America’s place in the world,” Kudlow told me.

Kudlow says he was struck by the parallels between Reagan’s message all those years ago and what happened in 2010, as once again Democrats overreached and suffered a historic defeat. All of this makes him wonder if Democrats will ever have a “Tony Blair” moment and make a conscious return to the political center.

After his Labour Party suffered three straight defeats, Blair took over as leader. He marginalized its left-wing extremists so the middle class could trust his party with power.

Mr. Blair told the Times of London he realized the “default mechanism” of Britain was closer to that of the Conservative Party, and that his party must move to the center. He then won three straight elections. But Labour returned to its class-warfare roots under his successor, Gordon Brown, and promptly lost the next general election.

So far, Democrats show few signs of thinking the U.S. is a country whose “default mechanism” in politics is to the center-right. They retain faith that Barack Obama can work some magic and make things better. But should he continue to slide in 2011 they may want to rethink matters.

After all, even though liberals despised the temporizing and triangulation that Bill Clinton practiced after his 1994 midterm losses, he remains the only Democratic president since the birth of ’60s liberalism to win reelection.