More and more congressional Republicans are joining Democrats in a desperate search for an Iraq exit formula.

Everyone recognizes the Iraq mess can be resolved only by a political pact between Sunnis, Shiites and Kurds – which isn’t on the horizon.

So the idea gaining traction is “soft partition”: pressing Iraqis to form three federal regions – with a weak central government. This would supposedly give each sectarian group control over its own turf and undercut the bloodletting. The idea has enticed both liberal and conservative pundits.

Indeed, the Senate just voted 75-23 for the Biden-Brownback amendment to the defense spending bill – the only Iraq amendment that has won major bipartisan backing – which urges our government to push for a “federal” solution to Iraq’s conflicts.

Unfortunately, the idea that soft partition offers a way out of the Iraq maze is wishful thinking. Any effort by Congress to press this plan on Iraqis will boomerang.

The amendment stems from a proposal put forward by Sen. Joe Biden and Leslie Gelb, former head of the Council on Foreign Relations, in 2006. It was based on the Dayton accords that resolved the Bosnian war. In that case, the United States “stepped in decisively,” Biden and Gelb wrote in the New York Times, with an accord that “kept the country whole by … dividing it into ethnic federations. … The idea, as in Bosnia, is to maintain a united Iraq by decentralizing it, giving each ethno-religious group – Kurds, Sunni Arab and Shiite Arab – room to run its own affairs.”

So Biden, D-Del., Sen. Sam Brownback, R-Kan., and their co-signers call for the creation of federal regions – as permitted by the Iraqi constitution. They also call for an international conference that would help Iraqis reach a political settlement based on this federalism premise.

The problem: Iraq is not Bosnia, and Iraq’s problems require a different solution. Let me say that I admire Sen. Biden, who has devoted more time and thought to the Iraq issue than anyone in the Senate. He rightly points out no one else has a viable plan for an Iraqi political solution, including the White House.

Yet – although the Biden-Brownback plan includes some useful ideas (more on this later) – a push for soft partition won’t get us out of Iraq.

Any outside pressure that appears aimed at dividing Iraq will create hostility there and in the region. No matter that Biden insists his plan isn’t aimed at a formal division of the country; most Arabs will regard it as a neocolonialist plot. This is why Iraqi Prime Minister Nouri al-Maliki – and the U.S. Embassy in Baghdad – were quick to condemn the Senate resolution.

As Iraqi Foreign Minister Hoshyar Zebari told me by phone on Monday, the resolution has “led to an uproar,” with Arab media claiming it represents a “Zionist plan” to divide the country.

Biden stresses that the “federalism” plan is based on Iraqi law and its constitution. But the Iraqi constitution lays out a bottom-up procedure for any provinces that want to join together in formal regions. Voters or provincial council members must instigate the process. Any outside pressure will be resented.

Of course, advocates of soft partition say the country is already headed toward partition. “Ethnic cleansing” has driven tens of thousands out of their homes in Baghdad and elsewhere. In the Sunni province of Anbar, tribal sheikhs are famously raising their own police forces; in the Shiite south, local militias do security duty.

So isn’t Iraq already headed for an ethic and sectarian split? The answer, like everything about Iraq, is messy. Despite ethnic cleansing, large areas of Iraq, including much of Baghdad, Mosul and Kirkuk, still retain mixed populations. To divide Iraq into three ethnic regions would require moving hundreds of thousands of people.

Most Sunnis and a majority of Shiites don’t want this. The Sunnis of Anbar, who have no oil, would still be dependent on a central government for funds, so they have nothing to gain from a more formal separation. Nor would soft partition stop the fighting, since the most violent sectarian militias want to control all of Iraq, not just a piece.

Equally important, Iraq’s neighbors don’t want a split. In the Bosnia case, the strongmen in neighboring Serbia and Croatia pushed their Bosnian proxies to accept soft partition. In the Iraqi case, Turkey, Iran, and Saudi Arabia strongly oppose any formal sectarian division of Iraq.

Yet one part of the Biden-Brownback resolution does holds promise: its call for an international conference to help Iraqis reach a political settlement.

The hope for Iraq lies not in international pressure for soft partition. That pressure should center on achieving an accord by Iraq’s Shiite and Sunni neighbors to stop fighting a proxy war within that country. This is the only way to stop Iraq’s bloodshed and induce Iraqi Shiites and Sunnis to agree on a political compact.

The good news is that 75 Senate members urged the White House to expedite such a conference. That should be the bipartisan focus, not the mirage of soft partition for Iraq.