Here we go again. In February, the Republican-led House of Representatives passed a budget that would eliminate federal funding for the Corporation for Public Broadcasting. That event tells you everything you need to know about the resignation this morning of NPR president and chief executive office Vivian Schiller. Yes, her underling Robert Schiller (no relation) embarrassed the organization by making some politically inexpedient remarks about the Tea Party, Republicans,and some more arcane issues, all captured on tape by conservative activists.

But at the average media organization, the “gotcha” video moment would likely have passed without the CEO’s resignation. Public radio is not the average media organization. It is held to an almost certainly unobtainable standard of objectivity, while commercial radio has thrived in recent decades by cultivating the most extreme political voices. It has a significantly larger audience than public television, yet receives a much smaller amount of public funding. And in order to further survival in its current form, it’s forced to regularly appeal to a relatively small number of legislators whose animosity toward it is deep and very public.

Radio has always occupied a peculiar place in American public broadcasting. Unlike, say, Britain, where radio was the original medium that created the audience-funded BBC empire, radio has never been the star of the American public broadcasting galaxy. As I documented in a book called Made Possible By…: The Death of Public Broadcasting in the United States, the Johnson Administration’s original draft of the Public Broadcasting Act made no mention of radio at all; a Johnson aide claimed that radio was hastily added the night before the bill was sent to Congress. All the emphasis was on television, a bias that the budgets for American public radio and television have displayed ever since. A public radio official in 1975 agreed with a Congressman’s assessment that public radio was “sort of a poor relative to public TV.”

At the same time, NPR’s news programs today enjoy audiences much larger than any regular program on public television. NPR’s “Morning Edition,” for example, claims a weekly audience of 14 million listeners, making it larger even than “All Things Considered,” which has been on the air longer (and celebrates its 40th birthday later this spring).  Cumulatively the NPR news audience is well over 20 million a week. NPR.org also claims a monthly audience of more than 9 million unique visitors (though many of those visitors are probably also NPR listeners).

How is it, then, that a media organization of this size and strength finds itself being pushed around so publicly and effectively by video pranksters and Members of Congress? After all, when the government created the current system of public broadcasting, it was designed to protect broadcasters against political interference through the CPB, which was intended as a “heat shield.” It has proven to be one of the least effective shields imaginable—in part because politicians of both parties have treated public broadcasting as a dumping ground for political patronage. (One of Schiller’s predecessors as president of NPR, for example, was Frank Mankiewicz, who had been a press secretary to Bobby Kennedy and had run George McGovern’s disastrous 1972 presidential campaign.)