The Federal Communications Commission voted to give the public online access to reports detailing new political ad buys from affiliates of the top four networks in the 50 largest media markets before November’s election, despite objections from the nation’s broadcasters.

The only hurdle now: the Office of Management and Budget must approve the new rule. After that, the top four stations in the biggest markets will put the ad buys on the Federal Communication Commission’s website. And the FCC expects that approval soon, William Lake, the chief of the media bureau, told reporters after the meeting.

After ...