The pressure is officially on U.S. Rep. Ahn “Joesph” Cao to vote for healthcare reform.

Over the course of the week, President Barack Obama has barnstormed the country for his comprehensive healthcare package with firebrand speeches outside of Philadelphia and St. Louis reminiscent of his campaign, in an attempt to get his signature legislation over a last few Congressional hurdles. (P.S. As a Philadelphia and unapologetic Obama-lover, I’d recommend the Philly speech if you want to get fired up.)

In concert with the President’s efforts, Organizing For America, the legacy of the Obama campaign’s celebrated grassroots infrastructure, has launched a massive effort to leverage bottom-up pressure on undecided House members.

The rollout of the effort has been tightly executed thus far, with each day bringing a separate and specific action. On Wednesday, “Day 1,” I was asked to print out fliers to hand out on my block. Today, on “Day 2,” I have been urged to call Cao.

This week I have received three e-mails, two phone calls, and a text message from OFA volunteers and organizers asking that I call Congressman Cao and urge him to support the President’s bill.

One might think that  Obama’s favorite Republican, and one who in December voted for the comprehensive bill that came out of the House of Representatives, would be enthusiastic about voting for health care changes this time around, but Cao is leaning toward a vote against.

Cao is reluctant now because the language related to abortion is not as explicitly restrictive as in the bill he voted for previously. His stance is similar to that of Michigan Democrat Bart Stupak, who is leading a coalition of anti-abortion Democrats that want to reach some sort of accommodation on abortion language.

Still, in spite of Cao’s consistently inflexible stance against abortion, it is hard not to probe the congressman’s incredibly unique political position. As a Republican representing an overwhelmingly Democratic district, he has had to vote carefully.

If he defies the president on the most important piece of his entire agenda, Cao is guaranteed to be dead meat in November.

Yet, he cannot simply vote with the president on every issue or switch parties without running the risk of alienating his financial contributors.

Then again, there is significant evidence that GOP fundraisers have taken advantage of the congressman by taking huge fees out of the congressman’s haul. Earlier this week, Cao ended his relationship with  the Washington firm that handled the money-sucking fundraisers, but not until after he had already spent $400,000 on its services, dwarfing the approximately $300,000 he actually has on-hand and available for his re-election campaign.

Given the likelihood of a strong Democratic opponent, his seat would remain very much in doubt even if he were to change parties to more actively support the president and vote the preferences of his constituents. Both State Reps. Cedric Richmond and Juan LaFonta have been quietly raising money and courting endorsements. Even if Cao were to join them as Democrats, they may not yield to him.

Yet as it is,  the congressman’s support for some of the president’s agenda – including his earlier vote for the healthcare changes – could result in a primary challenge from within the GOP, especially considering the purist nature of the contemporary conservative electorate.

As a result, Cao must be closely weighing his options, relying both on his conscience and his political self-preservation instincts as he considers his final vote on healthcare changes.