Although Mr. Cruz’s action cleared the way for the nominations to go through, it also appeared to stymie some Democrats’ efforts to get the commission, under Mr. Wheeler’s direction, to use its regulatory power to do what the Senate has failed to do. In 2012, Democrats fell a single vote short of passing the Disclose Act, which would have required the public disclosure of contributors to so-called super PACs, the anonymously financed lobbying groups that can engage in unlimited political spending independent of any candidate’s campaign.

At his nomination hearing in June, Mr. Wheeler dodged a question from Mr. Cruz about whether the F.C.C. had the authority to regulate political speech. “That’s an issue that I look forward to learning more about,” Mr. Wheeler said.

Critics of unlimited political donations have pushed the commission to fill in the blanks left by the Supreme Court’s 2010 Citizens United decision. F.C.C. regulations require that a television station “fully and fairly disclose the true identity of the person or persons or corporation, committee, associate or other unincorporated group or entity” that sponsors a political ad, and that the station post that information online.

But the F.C.C. has not said whether the requirement goes beyond the “I approved this message” tagline or the tiny gray type that appears on-screen at the end of most political ads.

In April 2012, the F.C.C. approved new regulations that required broadcast television stations to make their public service requirement files available online. Those files include information on the buyers of political advertising. Previously, stations were required only to maintain the files at their office and make them available for public inspection.

Some Democrats pushed for the commission to require more disclosure. But critics of the idea noted that the F.C.C. had authority only over broadcast channels — not cable stations, websites, newspapers or other media commonly used for political advertising.