In 2000, Al Gore let Karl Rove's operatives attack him with impunity. They peddled the Big Lie that he had claimed to have invented the Internet, and then mocked him for it, over and over again. They accused him of having been a liberal big-spender in the Senate, when his record was more centrist.
In 2004, John Kerry let the same group of thugs orchestrate an extended character assassination centered on the Big Lie that he had hyped himself as a Vietnam War hero and had exaggerated his battle wound in order to get a Bronze Star.
Kerry waited weeks before responding to the Swift Boat attacks. He thought it was beneath his dignity to defend himself.
By the time Kerry finally responded, it was too late.
This year, it looked like Barack Obama was a tougher, shrewder candidate. He went toe to toe with Hillary Clinton for months in the Democratic primaries; though she landed plenty of jabs and an occasional big punch, she couldn't knock him out.
So, why is Obama now doing his best incarnation of Kerry? Why hasn't he found his voice and responded forcefully, quickly and repeatedly to John McCain's relentless personal attacks, many of them based on lies?
John Kennedy and Ronald Reagan deflected attacks with humor, often with self-deprecating wit. Kennedy made Richard Nixon seem mean. Reagan made Jimmy Carter seem irrelevant. Bill Clinton made Bob Dole seem old and -- after initial stumbles -- Newt Gingrich seem crazy.
Obama doesn't need to mention McCain by name.
He could use a light touch in rebutting some of McCain's most vicious attacks, describing them as senile rantings.
Instead of using the weak claim that McCain "doesn't want to address the real issues that matter to Americans," Obama could say McCain has to focus on him because he has no substantive ideas of his own.
Obama should very publicly challenge McCain to join him in cleaning up the campaign and pledging to forego negative attacks. Obama should issue this challenge every day, at the end of every stump speech.
Obama should run an ad recalling Rove's smears against McCain in the 2000 South Carolina Republican primary. He should remind voters how angry McCain was, and how he's now reneging on his promises not to run similar campaigns.
With three weeks left in the 2004 presidential campaign, I flew to Florida to report on a crucial swing state. On the flight from Washington, I sat next to a Cuban-American from New York.
He was a successful, self-made businessman who said he'd come up on the streets of Queens.
He told me that he'd never voted for a Republican for president, but that year he was going to vote for Bush.
I asked why.
I'll never forget his answer:
"If John Kerry won't defend his personal honor, I don't trust him to defend our country."
He was right.
Are Democrats too principled to fight back -- or are they just wimps?