PBS recently added 15- to 30-second “sponsorship” messages to online presentations of major programs — everything from Masterpiece to Frontline (but not children’s programs). This fall, it intends to start interrupting its broadcasts with promotional spots, although in response to criticism it says it may test the idea first.

PBS calls these interruptions “program breaks” or “sponsorship announcements,” but on other channels they’re called commercials. So: What, in a world of hundreds of radio and TV channels, is so special about PBS and NPR that they should get $420 million a year of taxpayers’ money?

When I was a boy growing up in western Kentucky, with three TV networks, it was understandable that people thought an “educational” network would add something important. But my brother’s kids in that same little town later had access to hundreds of cable stations.

PBS used to ask, “If not PBS, then who?” The answer now is: HBO, Bravo, Discovery, History, History International, Science, Planet Green, Sundance, Military, C‑SPAN 1/2/3 and many more.

Defending its decision to include ads online, PBS says that it has more than 1,000 hours of online video, which “dwarfs anything anyone else has done.” Hardly.

C‑SPAN has more than 160,000 hours of video online. The Cato Institute has more than 2,000.

Yes, I listen to NPR every morning, I watched every minute of Downton Abbey and South Riding this spring — and I wrote rave reviews of the PBS documentaries Stonewall Uprising and Freedom Riders. I just don’t think my own cultural tastes deserve taxpayer support. I pay for HBO and Showtime; I put up with ads on CNN and Fox; I’m sure PBS could manage the same way.

Defenders of the tax-funded broadcast networks often point out that only about 15 percent of their funding comes from the federal government. Good — they can absorb the loss.

In 2003, NPR told potential advertisers that “compared with the general public, NPR listeners are 55 percent less likely to have a household income below $30,000 … 152 percent more likely to have a home valued at $500,000 or more and 194 percent more likely to travel to France.” And PBS viewers were 98 percent more likely to be a CEO and 315 percent more likely to have stocks valued at $75,000 or more.

Sponsors know this. The most prominent of the new online advertisers is Goldman Sachs, which knows where to find a wealthy and influential audience.

So why should working- and middle-class taxpayers be subsidizing the news and entertainment of the rich?

The main point here isn’t the money, it’s the separation of news and state. If anything should be kept separate from government and politics, it’s the news and public-affairs programming that informs Americans about government and its policies. When government brings us the news — with all the inevitable bias and spin — it is putting its thumb on the scales of democracy.

A healthy democracy needs a free and diverse press — but Americans today have access to more sources of news and opinion than ever before: more broadcast networks than before, cable networks, satellite TV and radio, the Internet. Any diversity argument for NPR and PBS is now a sad joke.

We don’t need a government news and opinion network. More important, we shouldn’t require taxpayers to pay for broadcasting that will inevitably reflect a particular perspective on politics and culture. The marketplace of democracy should be a free market, in which the voices of citizens are heard, with no unfair advantage granted by government to one participant.