CNN

Lieberman is a backer of McCain.

WASHINGTON (CNN) - Joe Lieberman is campaigning for John McCain, but he is digging into his wallet for Democratic senators.

Lieberman, a former Democratic vice presidential nominee, donated $115,000 to the Democratic Senatorial Campaign Committee this year, matching what he contributed to the political arm of the Senate Democratic Caucus in 2007, Lieberman's spokesman confirms to CNN.

Since leaving the Democratic Party in 2006 – Lieberman supporters have said the party left him – the Connecticut senator has crafted a new identity as an Independent Democrat. He is a prominent campaign surrogate for presumptive Republican nominee McCain, but still included in the Democratic head count that gives them a majority in the Senate by the slimmest of margins - one vote.

In turn, Lieberman chairs the Homeland Security and Governmental Affairs Committee - a powerful perch with wide jurisdiction over the Bush administration.

"Senator Lieberman supports both Democrats and Republicans, and he gave to the committee as a senior member of the caucus," Marshall Wittmann, Lieberman's spokesman, said Friday.

Lieberman was elected as a Democrat in 1988 and 12 years later found himself standing alongside Vice President Al Gore, as Gore's running mate. Six years later, it looked like his political career had come crashing down. His support for the war in Iraq prompted businessman Ned Lamont to challenge him in the Democratic primary. Lieberman lost.

But he vowed to continue running, a decision that caused many prominent Democrats, including fellow Connecticut Democratic Sen. Chris Dodd, to endorse Lamont. The endorsements weren't enough to seal a victory for Lamont - Lieberman was elected to another term.

The Politico, a Washington-based political newspaper, first reported news of Lieberman's six-figure DSCC donation.