After nearly six years on the air, liberal radio network Air America has gone bankrupt and will cease live programming, the company told employees Thursday.

Founded in 2004 as a liberal response to conservative dominance of the radio airwaves, Air America served as a platform for a number of liberal talkers who went on to achieve prominence, including now-Sen. Al Franken (D-Minn.) and MSNBC talk-show host Rachel Maddow.

"The very difficult economic environment has had a significant impact on Air America's business. This past year has seen a 'perfect storm' in the media industry generally," Charlie Kireker, chair of Air America Media, wrote in a letter to employees.

The network will air re-run programs until Jan. 25, at which time all programming will end. 

Kireker also touted the networks political impact.

"Through some 100 radio outlets nationwide, Air America helped build a new sense of purpose and determination among American progressives," Kireker wrote.

"With this revival, the progressive movement made major gains in the 2006 mid-term elections and, more recently, in the election of President Barack Obama and a strongly Democratic Congress."

Read the full memo to employees here.