NPR gets about 2% of its direct funding from the U.S. government, through the Corporation for Public Broadcasting. For NPR's member stations, CPB funding is about 10% of their total, with other federal, state, and local government sources kicking in another 6%.
This relatively tiny piece of money has been called "a critical cornerstone of public media." That was the stated position of Vivian Schiller—the NPR CEO up until today, when she was forced out, thanks to that government funding.
It's not worth it. As long as NPR takes a single dollar from the U.S. government, it will be forced to appease and cater to Congressional Republicans, who know that NPR is a convenient target in the culture war. And—newsflash—NPR will never be able to appease the Republican Party. It simply won't happen. The New York Times, America's finest overall news organization, is hated by Republicans. And Fox News, America's most fictional newsgathering operation, is beloved by Republicans. Appeasement is not on the horizon, unless NPR plans to become Fox News.
To argue over whether NPR is "liberal" is to waste everyone's time. Yes, it's liberal, and it does great journalism, and I wouldn't have it any other way. There's a very good reason why American news organizations have a long tradition of not accepting money from the government: because of exactly what NPR is going through right now. The Juan Williams fiasco. This week's farcical James O'Keefe "sting" that revealed that a non-news NPR employee held mainstream political opinions. And now, the (apparently forced) resignation of the CEO. The reason these were huge political controversies rather than mere run-of-the-mill media stories is that NPR is on the government payroll, and is therefore a voluntary target for every angry taxpayer with an asshole and an opinion. (All of them.)
Last week, NYT editor Bill Keller talked a bit of trash about Fox News. And if some Republicans in Congress don't like what he said? They can go fuck themselves, because what he said is true, and the NYT isn't going to lose any subscriptions over it. Fox News can defend itself quite well in the free media market. It's perfectly appropriate for news organizations of different ideological stripes to argue with one another, or to assert superiority, or just to poke fun at Rupert Murdoch's trench-like face wrinkles. It's part of what makes the media fun. Not satisfying everyone; saying what you believe, and backing it up.