Sen. Orrin Hatch (R-Utah), the top Republican on the Finance Committee, said Baucus should still be proud of such an enormous legislative victory, even though Hatch strongly opposes the healthcare law.
"He has to be," Hatch said when asked whether Baucus is still proud of the law. "I have to say, I have a different view of that bill, but it was a signal achievement, no use kidding about it. And he rammed it through the committee."
Republicans had made clear that their campaign against Baucus next year would focus heavily on his role in writing and passing ObamaCare.
Baucus seemed to be trying to insulate himself from that criticism last week, when he warned that the law could turn into a "huge train wreck" because of the way the administration has implemented it.
Sen. Ted Cruz (R-Texas) noted the "train wreck" comment when asked about Baucus's retirement.
"Decisions on retirement are for each individual senator to make, but I appreciate his candor last week in describing ObamaCare as a train wreck," Cruz said. "That is the reality that more and more Americans are seeing as this law is being implemented."
Baucus gets a lot more blame from the health law's opponents than credit from its supporters.
"He truly has been an unsung hero when it comes to the enactment of the Affordable Care Act," said Ron Pollack, executive director of the prominent advocacy group Families USA.
Baucus, along with the White House, was responsible for striking deals with various lawmakers and healthcare industries to secure their support for the legislation as it worked its way through his committee.
Those deals, while vital to the relatively limited opposition from healthcare groups, fed into a GOP narrative that the bill was being written behind closed doors and heavily influenced by lobbyists. The messy process is seen as part of the reason for the public's negative impressions of the law.
Baucus was also responsible for a long delay in negotiations over the bill. He allowed negotiations with Hatch and other Republicans to stretch on for months, long after the administration had given up hope of a bipartisan compromise.
Baucus's critics at the time warned that the delays were leaving the bill exposed to damaging attacks on the campaign trail and could end up killing it — all in pursuit of a bipartisan deal that wasn't realistic.
Pollack, though, said Baucus "made every effort" to forge a bipartisan compromise. Although Republicans never signed on, Pollack said, Baucus's aggressive courtship gave cover to reluctant Democrats who might not have supported the bill if there had been no effort to win GOP support.
— Erik Wasson contributed