Once upon a time there was something called “educational television,” which harnessed the technological marvel of a new medium to provide children and adults with edifying programming uncorrupted by advertising.

Today, public radio and television continue to devote more attention to educational programs than commercial broadcasters do, but they also seek to entertain viewers of all ages with features — such as British sitcoms, quiz shows, animal adventures and rock ‘n’ roll retrospectives — that duplicate those on commercial stations. And the programming is punctuated by corporate “sponsorship statements” that are advertisements by another name.

Given these changes, a federal appeals court decision this month allowing public stations to air political and campaign advertisements is not that dramatic a development. On April 12, the U.S. 9th Circuit Court of Appeals, by a 2-1 vote, struck down on First Amendment grounds a congressional ban on such advertising, while upholding a prohibition on ads by profit-making companies.

Under Supreme Court precedents, restrictions on free speech by federally licensed broadcasters must be “narrowly tailored to further a substantial governmental interest.” In this case, the asserted interest was Congress’ desire to preserve educational programming on public stations.

In the court’s main opinion, Judge Carlos T. Bea concluded that Congress had good reason to worry that the lure of revenue from ads for commercial products might induce public broadcasters to replace educational programming with fare more likely to garner higher ratings.

But Bea said there wasn’t “substantial evidence in the record before Congress” to suggest that children’s and other educational programming would be similarly endangered by a station’s acceptance of political ads. (He ridiculed the notion that a station eager for political ads might air a cartoon in which Mitt Romney or Barack Obama fought crime alongside Superman or Batman.)

One can accuse the court of not giving proper deference to Congress’ desire to keep public broadcasting ad-free. But even if this case had been resolved differently, the notion of public television as a safe harbor from advertising would be a quaint one.

In his concurring opinion, Judge John T. Noonan Jr. wrote: “As a viewer of ‘Jim Lehrer NewsHour’ and its successor, I have seen announcements that to my mind are ads. For example, I have viewed Charles Schwab’s message, ‘Talk to Chuck’ — it is not about Chuck’s golf game.”

From “Talk to Chuck” to “Vote for Barack” isn’t that big a leap. In both cases, one would hope that the proceeds from such advertising would be used to defray the cost of the educational programming that is still more common on public stations than on their commercial counterparts.