One of Hillary Clinton's last lines of defense against the onslaught that is Barack Obama is the notion that she has been "vetted" and he has not.
All the bad stuff that can be thrown at her already has been, she argues, and that gives her an advantage over Obama.
As Clinton said this week in a televised Politico/WJLA interview: "One thing you know about me is that I have been vetted. I've been through this. I understand exactly what is coming at me, and there isn't any new information. I mean, it's just more of the same. It's been recycled over and over again. I don't think we can say that about my opponent."
And, indeed, on Monday, Mark Penn, her chief strategist, released a memo saying that Clinton's having "withstood the full brunt" of the Republican attack machine is "one of the key arguments for Hillary's candidacy."
I think that may be wishful thinking.
First, even if one assumes all the old accusations about Clinton have been put to rest a dubious point she keeps raising new questions about herself.
Take the matter of her tax returns. Obama has released his, and Clinton won't release hers, she says, until after she is the Democratic nominee.
Why? She gives no reason. She says she files an ethics statement with the Senate, which is true, but so does Obama, and yet he also has released his tax returns. Clinton refuses to do so until after the Democratic convention.
Does this make sense to anybody? If she is going to do it eventually, why not do it now, while Democrats are still voting on her?
Keeping the returns secret just raises doubts and suspicions and kicks a hole in the case that she has been fully vetted.
But Obama also suffers from a little wishful thinking in believing that everything in his past has been fully explored and responded to.
"Look, I have been written about, I have been scrubbed, I have been vetted over the last year," Obama said on "Meet the Press" in December.
But he really hasn't. Nobody has. And that is because, in presidential politics, you never get "scrubbed."
Your past is dug up, reshaped and used against you.
Just in case the name no longer rings a bell, Willie Horton was a convicted murderer who was granted 10 weekend furloughs from prison in Massachusetts under the administration of Gov. Michael Dukakis.
The 10th time, Horton fled to Maryland, broke into a home, repeatedly slashed a man with a knife and beat and raped the man's fiancée. Horton was caught and sentenced to two consecutive life terms plus 85 years.
By the time Dukakis ran for president, he had already been "vetted" and "scrubbed" on the matter of Willie Horton and was sure it could not be used against him. The Lawrence, Mass., Eagle-Tribune had done more than 200 stories about it in 1987. And when Al Gore raised the issue in a New York primary debate against Dukakis, the Democratic crowd booed Gore and applauded Dukakis.
The issue never came up again in the primaries. But it sure came up in the general election, with a new spin. "The Horton case is one of those gut issues that are value issues, particularly in the South," Lee Atwater, who was George H.W. Bush's campaign manager, told me at the time. "And if we hammer at these over and over, we are going to win."
Similarly, John Kerry's Vietnam War service on a Swift boat had been raised against him for decades, and nobody gave it any credence. But it resurfaced in a new and virulent way when he ran for president.
The point I am making is that in a general election, no candidates get a pass on the past. They only think they do.
If John McCain gets the nomination, we are going to hear that he was turned into a "Manchurian candidate" when he was a prisoner of war. If Obama wins the nomination, we are going to hear a lot more about Tony Rezko and the Exelon Corp. And if Clinton is the nominee, get ready for a reprise of Whitewater and her cattle future trading, to name just two.
In presidential politics, the past is not just prologue. It's ammunition.