It was hard not to wince on Wednesday night as the two leading contenders for the Republican nomination, Mitt Romney and John McCain, danced around the opening question at the G.O.P. debate: After eight years under President Bush, are Americans better off now than they were eight years ago?

After considerable stalling, Mitt protested: "I'm not running on President Bush's record. President Bush can talk about his record." Not a full-throated endorsement, that.

McCain, for his part, said we are "overall better off," then proceeded to offer a long list of reasons why we aren't.

Meanwhile, in the Democratic contest, Hillary and Bill Clinton have been waging an all-out assault on Barack Obama - and the Democratic Party.

First, their campaign tried to use Obama's race to diminish his big victory in South Carolina, a tactic that was both racially insensitive and politically disastrous, because no Democrat can win the White House without the strong support of African-American voters. Worse, though, was the Clintons' brazen move to steal delegates in Florida - the state where elections go to die.

No delegates were being awarded in Florida, and all the Democrats had agreed not to campaign there, because the Sunshine State broke party rules by holding its primary so early.

It was foolish for party officials to disenfranchise a key swing state, rules or no rules. But it was also a decision supported by all the candidates, including Hillary Clinton - until she won the primary, that is, after which she proceeded to argue that delegates should be awarded based on the Florida results. (So much for Bill's old motto of "work hard and play by the rules.")

As Ronald Reagan once said: There you go again.

For two decades now, the Bushes and the Clintons have been passing the White House back and forth like a volleyball. But now, facing an eight-year extension of this bipartisan pas de deux, Republicans and Democrats have been coming to the same realization: The two families that have dominated American politics for the past quarter-century have not been good for their respective parties.

Last month, no less a conservative stalwart than Peggy Noonan, the former Reagan speechwriter and Wall Street Journal pundit, wrote, "George W. Bush destroyed the Republican Party, by which I mean he sundered it, broke its constituent pieces apart and set them against each other. He did this on spending, the size of government, war, the ability to prosecute war, immigration and other issues."

As The American Prospect dryly noted, this is the same Peggy Noonan who, in January 2003, lauded Bush for having a "steady hand on the helm in high seas, a knowledge of where we must go and why, a resolve to achieve safe harbor."

"More and more," she added, "this presidency is feeling like a gift."

Say it ain't so, Peggy; can this be the same man?

Alas, it is. The same Bush who had approval ratings above 90 percent just a few short years ago, who presided over expanding Republican majorities in Congress, whose chief strategist predicted a new era of Republican dominance, has left his party in its worst position since Watergate - and, perhaps, opened the door to another President Clinton. But at the same time as Noonan is surveying the Republican wreckage left by Bush, the Democrats are becoming hesitant about a Clinton Restoration.

After all, Bill Clinton came to office with Democratic majorities in Congress, but departed with the entire federal government in Republican hands. Bill's boorish behavior on the campaign trail is bringing back memories of the scorched-earth partisanship of the 1990s - and the Clintons' capacity for self-inflicted damage.

The leading liberal writer Josh Marshall, a staunch Clinton defender in the past, wrote last week that he is feeling "a mounting sense of unease verging into disgust with Bill Clinton's increasingly aggressive role in the campaign over the last couple of weeks." Clinton has abused the exalted elder statesman status of a former president, Marshall wrote, and is hurting his party in the process.

Indeed, while the first President Bush took great pains to keep distance between himself and his son's candidacy, Bill Clinton has placed himself at the center of his wife's.

That's why Democrats should think carefully about the Republicans' experience with a dynastic succession as they pick their own nominee this year.

Hillary Clinton, by all accounts a smart and tough politician, might make a very good president. But when one family is so powerful that its members will put their own interests ahead of their party's, the party had better move on.

TED NESI is a Sun Chronicle staff writer. His column appears on Fridays. He can be reached at tnesi@thesunchronicle.com.