Senate Democrats have chosen not to give Joe Lieberman a reason to leave the party:

Senate Democrats backed away from a major rebuke of Sen. Joe Lieberman (ID-Conn.) on Tuesday morning, keeping their colleague as the chairman of the Homeland Security and Governmental Affairs Committee in the next Congress and stripping him only of the gavel on a lesser subcommittee.

Though many Democrats and liberal activists wanted a tougher penalty for Lieberman’s disloyalty — his aggressive criticism of President-elect Barack Obama’s candidacy and his support of GOP presidential hopeful Sen. John McCain (Ariz.) — Senate Democrats ultimately voted to allow Lieberman to stay at the plum Homeland Security post.

Instead, Senate Democrats agreed to take away Lieberman’s top spot on the Environment and Public Works Subcommittee on Private Sector and Consumer Solutions to Global Warming and Wildlife Protection.

Senators approved the motion by a resounding vote of 42-13.

The Netroots are not taking the news well.