Senate Finance Committee Chairman Max Baucus stunned his colleagues Tuesday when he announced he would not seek a seventh term next year. But don’t expect him to go quietly.

Sen. Baucus (Photo by Mark Wilson/Getty Images)

Implementation of the 2010 health care law is a top priority for the Montana Democrat, as is overhauling the tax code, tackling the nation’s debt and pushing “job-creating trade agreements” through the Senate, Baucus said in a statement.

At a recent Finance hearing, Baucus predicted a “train wreck” coming with the health law’s implementation, and he said the Obama administration had done a poor job of implementing the law’s health insurance exchanges scheduled to be open for enrollment Oct. 1.

Baucus, who was one of the main authors of the 2010 health law, was expected to face a tough reelection campaign, and his support of the sweeping measure had raised some complaints in Montana. But he did include a provision to give Medicare coverage to people with an asbestos-related disease in the small town of Libby.

Baucus stands by his support of the law. On Tuesday, he told veteran Montana political reporter Chuck Johnson that the Affordable Care Act “is going to be well appreciated down the road.”

Dan Mendelson, chief executive of the consulting firm Avalere Health who oversaw health programs at the Clinton administration’s Office of Management and Budget, termed Baucus’s departure “a big deal” because he was one of a diminishing group of centrist lawmakers who knew how to work with members of the opposite party, even when it caused heartburn among his colleagues.

Baucus was one of just two Democrats – the other was former Sen. John Breaux, D-La. – whom Republicans invited to join a House-Senate conference committee that crafted the Medicare prescription drug program in 2003. Democrats criticized Baucus for helping the GOP to pass that proposal.

Now as then, with deep partisan divides in Congress over areas such as taxes and entitlements, having someone who knows how to navigate both sides of the aisle is a plus, Mendelson said. “Just at the time when you think it can’t get any more polarized, you lose a guy like Max Baucus who occupies the center,” he said.

Sen. Charles Grassley, R-Iowa, worked for 10 years with Baucus on the Finance panel, serving as both as its chairman and ranking member. During that time, “every bill except for three or four,was bipartisan,” Grassley said in a statement. “The Senate will be worse off as a deliberative body when Senator Baucus leaves.”