BOSTON — The governor of Massachusetts has picked former Democratic national chairman Paul G. Kirk Jr. to temporarily replace the late Edward M. Kennedy in the U.S. Senate, according to Democratic aides this morning.

The appointment by Gov. Deval Patrick will let Kirk, who was close friends with the senator, serve in the post until voters pick a permanent replacement in a Jan. 19 special election. It also gives President Barack Obama a critical 60th U.S. Senate vote he needs to pass his top legislative priority, a health care overhaul.

"He is intimately knowledgeable and supportive of the work that Sen. Kennedy was doing," said one of the aides, who, like the others, requested anonymity in advance of the official announcement. "He can start right away on that work. It's an opportunity in a short period of time to try to compete some of the work Sen. Kennedy has been working his whole life on."

Kirk, 71, served on Edward Kennedy's staff for eight years and is chairman of the John F. Kennedy Library Foundation's board of directors. He's a Boston attorney who also has been a registered lobbyist for pharmaceutical companies.

Kennedy died Aug. 25 of brain cancer.