Any senator can block the nominations on the Senate floor — they can only be confirmed with unanimous support.
Sen. Ted Cruz (R-Texas) has indicated he might block Wheeler's nomination unless he promised not to require more disclosure about the groups paying for political advertisements. Cruz's office did not respond to a request to comment Wednesday evening.
Wheeler is an investor and former lobbyist for the cellphone and cable industries. O'Rielly is a longtime congressional aide who currently works for Sen. John Cornyn (R-Texas), and McSweeny is currently an attorney in the Justice Department's Antitrust Division.
—Updated at 6:51 p.m.