With his new Iraq plan, President Bush has united the country. Pretty much everybody in America is now against him.

With good reason. Bush’s plan was a first-class blunder. The deal – we send an additional 21,500 troops in exchange for Iraqis making the same promises they failed to keep before – deserves the rejection it got in public polls and Congress. Bush’s worn-out, beaten-down look in Wednesday’s prime-time address was reflected in a plan that was short on logic and long on hope.

The president needs a rest and we need better ideas. If America were a parliamentary democracy, we would have a no-confidence vote and a new prime minister by spring.

Bush, already wounded, is now a virtual party of one. When Secretary of State Rice went to Congress to sell the Iraq idea, the only real difference between Democrats and Republicans was that the latter were more polite in leveling criticism. At the end of the day, Senate Foreign Relations boss Joseph Biden, D-Del., called the all-against-one tone “profound.”

Indeed it is. Only last year, Republicans watched in relative silence as his failure to change course in Iraq cost them Congress. Now they will not go meekly to the slaughterhouse if he is going to destroy the party for a generation.

Another illustration of his isolation was an op-ed column in Friday’s Wall Street Journal. Co-authored by two likely GOP presidential candidates in 2008, Rudy Giuliani and Newt Gingrich, the piece focused on rebuilding Iraq – but never mentioned Bush’s name! That could not have been an accident.

The turnabout is dramatic for Giuliani, who last spring said “George W. Bush will be considered historically a great president.” Even then, the “great president” line had to draw laughs in about 60 percent of American homes. Absent a miracle in Iraq, Giuliani won’t be saying anything like that again – unless he wants to commit suicide in 2008.

The mystery is why Bush failed to seize the chance to unite the nation around a new course in Iraq. The stage was set two months ago for him to do just that – and most Dems would have gone along because it made policy and political sense.

Bush started right by dumping Defense Secretary Donald Rumsfeld the day after the elections. The Iraq Study Group, led by family bailout specialist James Baker, gave him more running room by laying out some ideas he could accept, even if he couldn’t buy into the whole package.

But Bush suddenly went haywire and reverted back to stubborn type by putting all his chips on Iraqi Prime Minister Nouri al-Maliki. Just days after an aide wrote that the chaos in Baghdad “suggests Maliki is either ignorant of what is going on, misrepresenting his intentions, or that his capabilities are not yet sufficient to turn his good intentions into action,” Bush inexplicably dubbed Maliki “the right guy for Iraq.”

It was all downhill from there. The decision to send more troops and money is based on the need to crack down on death squads. Yet it was Maliki’s job and vow to do that. So we’re rewarding him again for making the same promise twice.

Apart from the obvious desire not to see Iraq totally unravel, the only explanation came from Rice. She told the Senate Bush believes Maliki’s problem is more one of capacity to do the job than will.

Fair enough, but that raises another question: If the main problem is that Iraqi forces are so unreliable in the sectarian fight, how will 21,500 more of our brave troops help?

They probably can’t, which is why a united Congress must tell the president no deal.