There are political upsides all around in such a bipartisan effort

Forget the Baker-Hamilton commission. I have high hopes for the Clinton-McCain Commission to Fix Social Security. Haven't heard of it? Actually, neither have Hillary Clinton and John McCain. It's my long-shot scheme for tackling the problem.

First, if not now, when? Third-rail political issues such as Social Security benefit from — maybe even require — divided government to share the blame. They can't be touched in an election year. They're difficult to do during a president's first term, if he — or she — wants a second. So 2007 offers the last, best hope for some time.

Second, if not Social Security, then what? The political system right now is too broken, and relations between President Bush and congressional Democrats too frayed, to deal with the truly daunting entitlement issues, Medicare and Medicaid. Social Security is entitlement reform on training wheels.

Third, if not them, who? As the front-runners for their parties' presidential nominations, Sens. Clinton, D-N.Y., and McCain, R-Ariz., have a shared interest in getting Social Security off the presidential plate before January 2009.

Clinton and McCain have a track record of bipartisan cooperation; working together on Social Security would only serve to burnish a credential that voters seem to crave. By teaming up, they could neutralize Social Security as a general election issue — neither could use it as a cudgel against the other. Both have expertise in this area without having burrowed into a rigid ideological framework.

Wouldn't each risk attack from rivals for the nomination? Yes, but the counter-argument is that voters will reward gutsiness and bipartisanship. So the short-term political benefits could offset — if not outweigh — the potential costs.

For McCain, the political peril is probably less than for Clinton, since his party hasn't made it a near article of faith that benefits can't be cut, retirement ages raised, payroll taxes diverted to private accounts, etc. He has more leeway to embrace alternatives.

For Clinton, the stakes are admittedly higher, but so is the upside. Sure, it's easy to imagine the ominous narration, "Hillary Clinton wants to slash checks for seniors," over the picture of a crying grandma. But some of Clinton's potential opponents serve in the Senate and might be swept along with the momentum of a bipartisan plan. And Clinton could use boldness on Social Security to combat her image as an overly careful, overly poll-driven calculator.

A bigger-tent commission — Clinton-McCain-Romney-Obama? — would be just fine, too.

So how to launch? The president should issue an order creating the commission, announce, LBJ-style, that he wants Clinton and McCain at the helm, and impose a tight deadline — six months at most. That sounds short, but the potential fixes and trade-offs are well known, and, politically, there's little time to spare.

Then he should set up the commission in a way that's doubly tilted against him.

For one, he should forswear any preconditions, which seems to be where the administration is already heading. There's no harm to the administration in dropping its focus on private accounts funded out of payroll taxes — that's the political reality. On taxes, similarly, there's not much to fear: The president has already opened the door to increasing the ceiling on payroll taxes, and the new Democratic majority will be wary of looking like rabid tax-hikers.

More than that, Bush should give Democrats a structural advantage. In a twist on the Greenspan Social Security commission, the president would appoint five members from the executive branch or private life; the Senate majority leader would pick five from among sitting senators or private citizens; and the speaker of the House would similarly name five. But, as with the Greenspan commission, two out of each five would have to be from the opposite party. This would create a commission of eight Democrats and seven Republicans, and drive the membership in a centrist direction.

Why would the president stack the deck against himself? Because he'd be giving Democrats an offer they couldn't afford to refuse — or be perceived as refusing. Democrats couldn't complain about being rolled by a Republican-dominated panel. Given the toxic level of distrust between the administration and congressional Democrats, it may be the only way to get action. And Bush could protect himself against Democrats Gone Wild by requiring a supermajority of the panel to agree on recommendations.

As it happens, the 25th anniversary of the executive order creating the Greenspan commission is Dec. 16. That would be a nice touch, too. And, Mr. President, senators, consider this headline that ran in The Post 16 months after the Greenspan panel was created: "President, on a Note of Bipartisanship, Signs Social Security Bill." Not a bad end to a troubled presidency — or a bad launching pad for a new one.

Ruth Marcus is a columnist for The Washington Post.