(New throughout with comments from hearing)
By Alina Selyukh
WASHINGTON, June 18 (Reuters) - Tom Wheeler, President Barack Obama's pick to lead the Federal Communications Commission, on Tuesday pledged to champion competition in the telecommunications industry and said an upcoming auction of airwaves is the biggest challenge facing the regulator.
Acknowledging his past as a lobbyist, Wheeler told lawmakers at a Senate Commerce Committee hearing on his nomination that at the FCC, he would advocate for the consumers' interest first: "My client will be the American public."
Committee Chairman Jay Rockefeller, a West Virginia Democrat, said he was certain the Senate would approve Wheeler to succeed Julius Genachowski as FCC chairman.
The next step for Wheeler will be a vote by the committee on his nomination. No date has been set.
Asked to cite the single biggest challenge facing the FCC, Wheeler pointed to the so-called incentive auction, during which U.S. broadcasters would give up some of their airwaves to be sold to wireless providers.
Wheeler called the complex auction process a Rubik's Cube, because the rules that are currently being drafted would have to take account of the many interests at stake.
The FCC has planned this biggest-ever spectrum auction for 2014, although many in the industry say its complexity could mean delays. Wheeler pledged to make every effort to meet the 2014 deadline.
"I understand the concerns," Wheeler said, adding that he was involved in the FCC's very first spectrum auction, which was held in 1994. "This isn't my first rodeo."
Wheeler, who was recently a venture capitalist and an Obama fundraiser and adviser, was a top lobbyist at the National Cable Television Association in the 1980s and then at the wireless industry group CTIA until 2004.
"I am an unabashed supporter of competition," he said. "The role of the FCC has evolved from acting in lieu of competition to dictate the market, to promoting and protecting competition with appropriate oversight to see that it flourishes."
Senator John Thune, a Republican from South Dakota, pressed Wheeler about his 2011 blog post in favor of a merger of top wireless providers AT&T Inc and T-Mobile that was ultimately blocked because of concerns about competition.
"There is scarcely anything more important that comes before the commission than merger review," Wheeler said, adding that the blog was a "hypothetical speculation." He cited three factors crucial to merger review: deal-specific facts, legal mandate and precedent.
Addressing a critical issue he will have to tackle as FCC chair - decades-old rules that limit cross-ownership of different U.S. media outlets in one market - Wheeler said he understood the seriousness of the issue and was "specifically trying not to be specific." "I want to become more informed," he said.
Asked by Republican senators about attempts by Democratic lawmakers to get the FCC to press TV stations to disclose sponsors of political ads - a hot partisan issue - Wheeler said he needed and planned to study the topic to determine whether the commission should act, or has the authority to do so. (Reporting by Alina Selyukh; Editing by Ros Krasny and Steve Orlofsky)