The White House called a press conference today, and Obama the candidate showed up.

After explaining his tax-cut compromise last night in calm, measured tones, the Obama who came to the podium today spoke with fire and force, offering blunt, cut-and-dried assessments of why he decided to cut a deal with Republicans and renew high-income Bush tax cuts for two years (despite promising otherwise on the campaign trail), in exchange for extended unemployment benefits, a payroll tax cut, and other, smaller tax cuts aimed at middle-class families.

Obama took the stage as congressional Democrats continue to resist the deal, and he fielded questions from reporters about members of his own party attacking his fortitude - attacks that date back to the long process of reforming health care.

"If that's the standard by which we are measuring success or core principles, then, let's face it, we will never get anything done," Obama said. "People will have the satisfaction of having a purist position and no victories for the American people, and we will be able to feel good about ourselves and sanctimonious about how pure our intentions are and how tough we are, and in the meantime the American people are still seeing themselves not able to get health insurance...not able to pay their bills. ...

"That can't be the measure of how we think about our public service. That can't be the measure of what it means to be a Democrat. This is a big diverse country. Not everyone agrees with us. I know that shocks people."

After getting savaged for over a year for various and opposing reasons--from failing to pursue the public option more sternly, to pushing health care reform through Congress despite its unpopularity in national polls, to failing to engage the Republican Party and change Washington's partisan rancor, to, finally, assenting to a temporary extension of the high-end Bush tax cuts--Obama appeared to be sick of this. The president looked as if he was done trying to navigate any political currents whatsoever. He looked like his back was actually against a wall.

Obama typically explains his decisions in calm, rather aloof tones. That's the kind of guy he is. He doesn't get too worked up in public. Today, his attitude was: look, this is how it is.

Much of this was directed at Democrats. After he went on live, national TV last night to outline this deal, there are no signs that congressional Democrats are actually buying it. The House Democratic caucus hasn't signed off on it, asserted Rep. Chris Van Hollen, the incoming ranking member of the Budget Committee, in an interview with Bloomberg TV this morning. The two incoming co-chairs of the House Progressive Caucus released a statement opposing the temporary extension around midday.

"I would speak especially to my fellow Democrats, who I think are rightly passionate...the single most important jobs program we can put in place is a growing economy," Obama said, criticizing those who would prefer a "protracted political fight" that jeopardizes unemployment benefits and an extension of the Bush-era tax cuts for earnings under $250,000. The president did stress, however, that he understands where reluctant Democrats are coming from.

"There are people right now who, when their unemployment insurance runs out, will not be able to pay the bills. There are people right now who are just barely making it right now on the paycheck they've got, and when that paycheck gets smaller on January 1, will have to start scrambling," Obama said.

This press conference was probably the beginning, in a very general sense, of Obama's 2012 campaign season: He took the occasion to criticize Republicans as forcefully as he's done in months, drawing some sharp contrasts of policy.

"This is their holy grail," Obama said of GOP-supported tax cuts for the wealthy. "The problem is that Republicans feel that this is the single most important thing that they have to fight for as a party."

And Obama pointed to major national polls, all of which show the public supporting his position on the tax cuts.

"The issue is not me persuading the American people," he said. "They're already there."

Promising to fight over the tax code during the next two years, it was clear that Obama thinks this is a winning issue.

The press conference was an odd blend. On the one hand, he was selling a compromise. On the other hand he rhetorically bludgeoned the very people he was compromising with. In presenting the deal that, several weeks ago, was conceived as a moment when Obama would tack to the center in response to the midterm elections, reaching across the partisan divide and changing his approach in an effort to heal the partisan tone, Obama came out denouncing Republicans with more energy than we've seen in quite a while, after announcing it with only a couple hours notice in an attempt to pressure Democrats to support it.

He was trying to sell, or re-sell, fellow Democrats on the deal he introduced last night, seeking to stave off an embarrassment to his presidential clout if they don't support it. But in bringing up the unpopularity of the GOP's position, Obama sought to relentlessly exploit what he clearly sees as a political weakness in the Republican Party's policy platform.

Obama worked the bully pulpit in both directions, and the intensity flashed toward both sides.

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