What worked for P.T. Barnum didn’t do as well for Sen. Hillary Rodham Clinton (D-N.Y.). When the great showman said, “Nobody ever went broke underestimating the intelligence of the American people,” he unknowingly anticipated the fundamental assumption that underlay the campaign of the first woman seriously to contend for the presidency. But however correct Barnum’s observations may have been about the circus audiences of years ago, it has proven a flawed premise for a 21st century presidential campaign.

From the very beginning of her solo political career, Hillary Clinton has manifested a consistently low opinion of the intelligence of voters. Sometimes the bet has paid off — as when she tried to convince New Yorkers that she wanted to become one of them (when, in fact, she would have run in Montana had there been a vacancy). But lately, it hasn’t. Her entire decision to predicate her campaign on the basis of her so-called “experience” reflected a belief that she could put one over on us by co-opting Bill’s experience and making it her own. So enticed was she by the prospect of attacking Obama for his lack of tenure in federal office that she didn’t stop to notice that she didn’t have much more than he did and could only make her point by exaggeratin g her role in her husband’s administration. Small matter. She was so confident that she could pull off the deception that she premised her entire campaign on her ability to do so.

In all matters but the most personal, Bill Clinton never played down to voters. His 1992 campaign mantra — the need for a New Democrat — addressed frankly the failures of the party for the past two decades. Facing globalization, he didn’t talk down to the electorate but explained the nature of the new situation and articulated the ways in which we had to become competitive to meet it.

But Hillary always tries to put one over on us. She refused to release her financial records and tax returns and figured we’d never notice. She spoke vaguely of her sympathy with those who wanted to issue driver’s licenses to illegal immigrants and bet that the media would never force her to articulate a real position.

Hillary tried to make her insistence on mandatory health insurance the lynchpin of her differences with Obama and assumed that she would never have to explain how she would enforce it. Her campaign was funded by lobbyists — and Obama’s was not — but she guessed that it would never become an issue. She and Bill kept dropping hints about racial issues in the campaign, but they decided nobody would call them on it.

Mrs. Clinton believed that she could support the Iraq war until moments before her presidential candidacy began and that the anti-war movement would welcome her as one of their own anyway.

The Clintons’ entire approach to this campaign season was based on learning the wrong lessons from their political history. They survived the Lewinsky imbroglio, the pardons scandal, and the theft of White House gifts and assumed they were bulletproof. They confused our forgiveness with gullibility and came to feel that they could get away with anything. When Hillary won her Senate seat in New York, after Giuliani dropped out and Lazio could offer only nominal opposition, she believed she could sell voters any kind of chimera and they would fall for it.

But she assumed wrong. We saw through her claims of experience and followed her twists and turns on Iraq. We realized that she was being propped up by lobbyists and special interests as a phony brand of change. And when we saw the real kind of change offered by Obama, we backed his candidacy.

Maybe we were never quite as dumb as she thought we were.

Morris, a former adviser to Sen. Trent Lott (R-Miss.) and President Bill Clinton, is the author of Outrage. To get all of Dick Morris’s and Eileen McGann’s columns for free by e-mail, go to www.dickmorris.com .