Obama's Intended Audience: 100 House Democrats...

Democrats -- and, in particular, the 100 or so liberal Democrats who have threatened to oppose a bill that doesn't include a public option -- are the main target of the president's persuasion tonight. Why? Legislative math.

As Ron Brownstein points out, in 12 years of governing, Republicans never had more than 235 House seats. Democrats have 257 today. Some of them are way out in the hinterlands, forcing the occupants to vote "no" on virtually every major initiative that's tagged as Democratic. There are about 25 of these seats -- lost causes, from the point of view of the White House. Looking back at the cap-and-trade vote, Nancy Pelosi lost 64 Democrats and picked up 8 Republicans.

With the possible exception of Rep. Joseph Cao, the White House doesn't expect to get any Republican House votes on health care (though they will try to pick off a few). So they can safely lose about 50 conservative Democrats... providing that every liberal Democrat votes yes.

And though the White House took House liberals for granted in August, they now believe that getting these liberals to stop talking about the necessity of a public plan - to stop equating a public plan with insurance reform - is as major an obstacle to getting a good bill done as the 60 vote threshold in the Senate.

Realistically, will a speech by the president of the United States change Olympia Snowe's mind on health care? Or Chuck Grassley's? No. Snowe will look at the final language, and Grassley will weigh his political philosophy and party unity against the accomplishment of providing health care for all.  Outreach to these Republicans is best conducted privately, and the President has no illusions about being able to sway public option significantly enough to cross-pressure Senate Republicans.

So, the case the President will make tonight will be basic, and by default, progressive.  We're almost there, he'll say. Major new subsidies for those who can't afford insurance. Restrictions on the industry that progressives have been wanting for years, like an end to community rating and guaranteed issue and no dropping of coverage.  The promise of fulfilling a generational promise - Ted Kennedy's vision.  To keep insurance companies accountable, he'll talk about the need for some sort of competitive mechanism. He say that he'd strongly prefer that it'd be a public option, and that the final bill must set the foundation for more competition in an industry that has largely been immune from it.   I suspect that Obama will discuss the subsidies in detail.  And you can bet that he will challenge opponents of reform to support what's been broadly agreed to or stop demagoguing health care for political reasons. (Democrats will like when Obama challenges Republicans.)

Right now, Gallup has the number of Americans who say they'd instruct their member of Congress to vote "yes" at 36% and the number of people who say they'd instruct their member of Congress to vote "no" at 37%. The rest are undecided --- even after the bruising month of August, where the bill was defined largely in terms unfavorable to Democrats. Constituents of these liberals overwhelmingly support the bill.

He'll still try to smoke out some Republicans... by talking about tort reform and cost containment. The intended audience here is less the people in the room than the people watching at home.