Aides tell NBC News that Iowa Sen. Tom Harkin will replace the late Edward Kennedy, a fellow liberal Democrat, as chairman of the Senate health committee — a key panel in the president's push for an insurance overhaul.
Connecticut Sen. Christopher Dodd reportedly decided not to succeed Kennedy, his close friend and mentor. Instead, he will remain at the helm of the banking committee.
Dodd faces a potentially tough re-election fight next year and has used his chairmanship to champion such populist issues as tougher credit card laws.
Harkin's old-fashioned progressivism is not unlike Kennedy's. Harkin would have to abandon his post as chairman of the agriculture committee.
In recent years, Harkin has used his chairmanship on the agriculture committee to aid family farmers. And as a senior member of the health committee who helped Kennedy draft the panel's bill, Harkin has said the legislation must include a public insurance option.
"I think that's the essential part of health reform, and that is to have one public plan that is portable. No matter where you live, no matter where you move, you know you can get this plan," Harkin told reporters this summer.
Harkin also is known for his ardent defense of embryonic stem cell research. In 2006, Harkin worked with Pennsylvania Sen. Arlen Specter, then a Republican, to push through legislation that would have lifted restrictions on federal funding for the research. President George W. Bush vetoed the bill.
Harkin's departure from the agriculture committee could hand that chairmanship to Sen. Blanche Lincoln of Arkansas, a more moderate Democrat but staunch supporter of government farm subsidies. The new post would be a boon for Lincoln, who faces a potentially tough re-election fight next year and could use the committee perch to aid Arkansas farmers.