WASHINGTON — Astonishingly, 26 Republican senators broke with President Bush’s Iraq policy last week. But you may not have noticed this, and it’s not your fault.

Sen. Joe Biden’s resolution calling for a federal solution to the Iraq mess — sometimes known as “soft partition” — got almost no attention even though it passed 75-23. There seems to be far more interest in how fundraising is going for Hillary Clinton, Barack Obama and John Edwards.

The vote on Biden’s proposal to devolve power to Iraq’s regions and three major groups could turn out to be a milestone in the effort to end the war. It was also a reflection of how much Republican frustration there is with the Iraqi government and the direction of President Bush’s policy.

From the beginning, Bush has insisted that Iraq’s current crop of politicians could broker peace among Shiites, Sunnis and Kurds, and make a strong central government work. But that idea is increasingly implausible. The administration’s deeds (as opposed to its words) are a tacit admission of failure.

Bush’s claims for the success of his troop surge rest in large part on the alliance between American troops and Sunni sheiks in Anbar province in the battle against al-Qaida in Iraq. Yet this bottom-up side deal has nothing to do with a strong central government, and may actually work against it.

In an interview, Biden said he was not surprised that so many Republicans backed his nonbinding resolution. He believes that there are “not a dozen Republicans” who still think privately that “an American presence in Iraq will maintain a strong central government.”

The biggest problem with federalism — Biden rejects the term “partition,” believing that a weaker central government is the only way to maintain even a semblance of unity in Iraq — is that Iraqis themselves have not yet come around to the idea. Over the weekend the Iraqi government forcefully condemned the Senate’s action. Partition or decentralization will not easily be imposed by the United States, or even by a concert of allies.

This does not deter Biden, who on Monday joined his co-sponsor, Sen. Sam Brownback, R-Kan., in asking for a meeting with Bush on the resolution. Biden insists that the logic of decentralization is gaining ground among Iraqis, despite what their government is saying, and cites an encounter with a prominent Sunni leader during a recent visit to Iraq. Shortly after publicly criticizing Biden’s decentralization proposals, this leader told Biden privately: “My heart is at war with my head.” Biden said the Iraqi saw decentralization as the only practical way out of the current chaos. The official added: “I need time to convince my people.”

Biden’s clarity stands as a challenge not only to Bush, but also to Clinton, Obama and Edwards. At a debate last week, each of them refused to pledge that American troops would be out of Iraq even by the end of her or his first term. If the troops will still be there, what strategy would they be advancing? If not federalism or “soft partition,” what? Clinton, by the way, voted for the Biden resolution, while Obama missed the vote. Will federalism be Clinton’s approach, too?

And if Biden is creating pressure on the front-runners from one direction, Gov. Bill Richardson of New Mexico is beginning to gain traction on the left with his commitment to withdrawing all troops “in six to eight months,” as he wrote last month in The Washington Post.

It’s surprising that Richardson, whose domestic views are by most conventional reckonings to the “right” of much of the field, could ever become the left’s favorite. But he has risen in the polls in Iowa and New Hampshire, partly because of effective early advertising, and may now have a chance to catch on with anti-war voters.

John Nichols, one of the left’s shrewdest electoral analysts, argued in the Oct. 8 issue of The Nation that “The Richardson Surge” would make it difficult for the front-runners “to continue dancing around the core questions of the war.”

The leading Democratic candidates might well argue that Bush has made such a mess of Iraq that the seemingly crisp and clean solutions on offer from Biden and Richardson simply aren’t workable.

But there is no getting around how important Iraq is to so many Democratic primary voters. They are looking for well-defined alternatives to Bush’s recipe for troop commitments as far as the eye can see. Biden and Richardson are trying to fight their way into contention by offering very different visions of a future that might allow us to leave.

E.J. Dionne’s e-mail address is postchat(at)aol.com.