The disclosure rules would not apply to political advertising on cable channels or websites, which do not use public airwaves.
Dingell and Green asked Genachowski to explain why the proposed rule targets only broadcasters and whether the commission has considered applying the disclosure requirements to cable and satellite channels.
They suggested partial disclosure could mislead the public about how much campaigns are spending on political advertising
Rep. Jo Ann Emerson (R-Mo.) grilled Genachowski about the proposed rule during a hearing on Monday.
"Why do you care about this? You have plenty of other things that are far more important since we already have a Federal Election Commission," she said. "Why in the world is this a big priority?"
During the hearing, Genachowski said the proposal is part of the commission's effort to increase transparency and put more data online. He said the proposed rule would allow academics, journalists and members of the general public to more easily find out which groups are buying political ads and how much they're spending.
"In the 21st century, the question is if common sense says to put that information online," he said.