Public broadcasters like NPR and PBS may get sucked deeper into the political fray this election season -- and not just during programming.

A federal appeals court in California Thursday opened the door for broadcast stations to air paid public issue and political advertisements that had been banned from public airwaves along with corporate ads.

The ban on most paid commercials aims to keep educational content on public broadcast stations. If broadcasters were dependent on corporate advertising dollars, they would air programming with mass-market appeal, the government contends.

A panel of judges on the 9th Circuit Court of Appeals said in a split decision the 1980s ban on issue and political ads has a tenuous connection to the government's efforts to maintain quality programming on the public airwaves, unlike the still-standing ban on ad dollars from for-profit companies. Further, the court majority could not square away a prohibition on political advertisement with allowing nonprofits to buy air time on public airwaves.

Public issue and political speech in particular is at the very core of the First Amendment's protection, wrote Judge Carlos Bea in the 2-1 decision.

Should the ruling stand, public broadcasters could take ads from Super PACs, that have already left an indelible mark on the 2012 presidential election season. That was a concern for the judges who struck down part of the public broadcasting ad ban.

We see how a news broadcaster may be tempted to alter the content of its public affairs programming if it thinks it can garner additional advertising dollars from one or another campaign, Super PAC, or advocacy group by doing so, Bea wrote. But speculation aside, there is no evidence in the record ... to support Congress's specific determination that public issue and political advertisements impact the programming decisions of public broadcast stations.

The challenge to the ad ban came from Minority Television Project, a nonprofit group that operated San Francisco-based KMTP. The broadcaster was hit with a $10,000 fine from the Federal Communications Commission for airing commercials from companies like Chevrolet and State Farm insurance.