GOP Senator Susan Collins is considered a key target by national Dems sizing up the 2008 elections, but at least one Democrat (of sorts) will be helping Collins play defense: Joe Lieberman. From the Associated Press:

Connecticut Sen. Joseph Lieberman said he is endorsing Sen. Susan Collins in her 2008 re-election bid and will campaign on her behalf.

Lieberman, a former Democrat turned independent, is returning the favor to Collins, a Republican who supported and campaigned for him in his 2006 election in Connecticut...

Lieberman told the National Journal's "CongressDaily" on Thursday that he is ready to support Collins even though he doesn't know who the Democratic nominee will be. He said his political action committee has contributed $5,000 toward Collins' campaign.