No matter how well Clinton does in the remaining primaries, her future is going to be in the hands of the superdelegates. It's time for them to exercise their power to rein in scorched-earth campaigning.

Oregon Congressman Peter DeFazio recently criticized both Clinton and Obama in a public letter for allowing "the long-term goal of beating the Republican nominee [to take] a back seat to the short term goal of proving one's viability by tearing down the other Democratic candidate.

"Run the next six weeks of your campaign against McCain," DeFazio urged, "not against the other Democrat. Go after McCain for his policy positions, not the other Democrat for theirs. Allow the Democratic voters to believe in a campaign that can provide a new direction for this country and stop McCain from continuing the failed policies of the Bush administration. In the end, it is the candidate who can take the fight to McCain and win that deserves my support and, most importantly, the support of the Democratic Party."

This is where other superdelegates could help. Since what the New York Times recently called Clinton's increasingly narrow path to victory depends on her overwhelmingly sweeping those still undecided (aided in part by Rush Limbaugh and Fox supporters crossing over to support her in the remaining primaries, as they have since Ohio & Texas), they could stop the Democratic blood-letting by lining up behind Obama now. At that point, the battle for the nomination would end, and Obama would have seven months to focus on defeating McCain. I'd like to see as many as possible do this, but if they want to wait until the last primaries are run, DaFazio's letter suggests another alternative.

A significant group of uncommitted superdelegates (and maybe some committed ones) could follow DaFazio's lead and make a public statement condemning the destructive campaigning. They could make clear that either candidate who attacked the other enough to seriously benefit McCain would immediately lose their support.

Those who signed such a statement would still keep their autonomy. They could still endorse whomever they preferred between Obama and Clinton, and do so in their own time frame. But they'd be making overt what most Democrats are feeling--that the Party can't afford to tear itself apart in the process of selecting a nominee. It can't afford to give credence to Republican talking points or so stoke the mutual demonizing that Democratic voters end up staying home, or even vote for McCain. Because the superdelegates would be responding to negative attacks with their votes, this just might put enough teeth into their responses to deter them.

This shouldn't be necessary. Barack Obama just gave an amazing speech that looked deep into his life to ask the hardest imaginable questions about race, class, and faith, who we are as Americans, and who we want to be. This speech seemed to touch people in a way that's rare in our political life, and open up at least the possibility of becoming a watershed moment America's march toward greater justice. I'd have no problem if Clinton continued to compete with Obama by offering her own take on the issues he's raising and others of similar consequence.

But I doubt that will happen. Given Obama's nearly insurmountable lead in elected delegates, I suspect Clinton will soon be back pursuing the massive personal attacks that seem her only chance to damage Obama enough to give the superdelegates second thoughts. And the media, especially the broadcast media, will likely buy in, because they'd rather report on mud-wrestling than on political arguments.

Last week, in Harrisburg PA, Hillary whipped up a crowd to boo Obama, something I've never witnessed in a Democratic presidential primary. In Youngstown, OH, a couple weeks before, she stood by and said nothing when Machinist's Union head Tom Buffenbarger introduced her at a rally by calling Obama supporters (in language taken from recycled anti-Dean ads of the right-wing Club For Growth), "latte-drinking, Prius-driving, Birkenstock-wearing, trust fund babies." And writing the Republican script, she's argued that she and McCain are ready to be Commander and Chief but Obama is not. If Clinton and her supporters are saying these kinds of things about Obama now, it's going to be tough for them to turn on a dime and encourage voters to unite behind him come November.

By the same token, to the degree that Obama seriously returns the fire, and continues to do so, that similarly damages Clinton's chances, should she become the nominee. As a friend who supports Clinton said, the situation risks both the candidates and their passionate supporters becoming "intellectual arms traders in the aid of John McCain."

So DaFazio's approach makes sense. But he needs other superdelegates to sign on or issue their own statements, to magnify the impact. They don't have to entirely ban all drawing of distinctions, because real policy differences exist. But they need to make clear that whatever destructive attacks gain in primary votes, they'll more than lose them at the convention. Drawing this kind of line may be the only way that the Democrats can begin to pull together again, and end the disastrous stands of Bush's past seven years.