Which Senator holds the most sway over Barack Obama's domestic policy agenda? The answer probably isn't Hillary Clinton, Ted Kennedy, or even Harry Reid. Instead, as Ezra Klein points out in a lengthy feature piece today, it's probably Max Baucus.

Baucus is chairman of the Senate Finance Commitee, whose jurisdiction includes virtually any legislation that requires raising or lowering taxes. Middle class tax cuts. Universal health insurance. Cap-and-trade. Pretty much every big promise Obama made on the campaign trail will go through Baucus' committee.

If you're a liberal like me, and you're hoping Obama will be able to deliver on his ambitous promises, this news may not be the most comforting. During the early years of the Bush Administration, Ezra notes,

He partnered with Republican Chuck Grassley to craft President George W. Bush's first tax cut and angered the Democratic leadership by refusing to consult them before the bill's markup. He further infuriated his party by helping Republicans pass the Medicare prescription-drug bill even after they had locked the Democratic leadership out of conference committee. He voted for the 2005 bankruptcy bill. For his sins, The Nation has branded him "K Street's Favorite Democrat." This magazine termed him "Bad Max." The New Republic editorialized that he should be stripped of his chairmanship.

More recently, though, Baucus has taken up the Democrats' cause with relish. He helped lead the charge against President Bush's efforts to privatize Social Security. In the profile, Ezra captures Baucus not just talking about this episode, but boasting about it with glee:

When I meet with Baucus at the City Grille in Denver, he is eager to emphasize this chapter in his story. "When Reid put me in charge of stopping the privatization of Social Security, man that was fun. That was the right thing to do," he says. "I remember President Bush came to Great Falls, Montana, and I set up a meeting with seniors at the same time, just across town, just right in his face. I relished the opportunity just to beat down privatization flatly and squarely." His message is clear: I can fight.

Of even more significance going forward may be Baucus's recent dealings with Charles Grassley, the ranking Republican on Finance, over last year's Medicare payment adjustment. Baucus has always prided himself on his strong working relationship with Grassley, a relationship that has endured changes in partisan control of the Senate. And last year, when it was time to tweak Medicare in order to avoid a drastic cut in physician fees--something the government has done routinely, over the last few years--Baucus assumed the two could work out a deal once again.

But the White House opposed the fix, because it would have reduced some payments to health insurers. And Grassley, to Baucus' dismay, was playing along, dragging his feet in what looked to a lot of outsiders like a big game of chicken. (Republicans figured Democrats would cave, rather than risk letting the physician fee cut take effect.) Fed up, Baucus bypassed Grassley and sent the bill to the floor, where Kennedy--coming straight from the hospital in Massachusetts--cast the deciding vote to pass.

This bodes well for the key role Baucus will likely play in health care reform. Last year, Baucus launched a series of hearings, with the very explicit goal of preparing his committee members and their staffs for a serious run at universal coverage in 2009. As Ezra reports, and I have heard as well, within the health care policy community even the most skeptical observers say they are impressed with Baucus' efforts to date. Amazingly, Baucus is even talking about pushing health care reform through the budget reconciliation process, a partisan move that would prevent Republicans from using the filibuster.


--Jonathan Cohn