(Reuters) - U.S. lawmakers will delve on Thursday into an international debate on whether to hand more control of the Internet to the United Nations, a move many fear would turn it into a political bargaining chip for censorship and global taxes on Web companies.

U.S. government officials are gearing up for a December meeting in Dubai where delegations from 193 countries will discuss whether the UN should have more say over how the Internet is organized and controlled.

Critics say that, under such a regime, each nation regardless of size has one vote, which could give China, Russia, Iran, Saudi Arabia and other countries greater ability to isolate their populations and silence political dissidents.

"What proponents of Internet freedom do or don't do between now and then will determine the fate of the Net, affect global economic growth and determine whether political liberty can proliferate," Robert McDowell, a Republican commissioner on the Federal Communications Commission, said in testimony prepared for Thursday's hearing.

A House Energy and Commerce subcommittee is holding the hearing in what will be one of the highest-profile airings so far in the United States on the coming debate at the World Conference on International Telecommunications (WCIT) in December.

The U.S. government is trying to drum up support, both domestically and internationally, to preserve a decentralized Internet.

Obama administration officials held a closed-door meeting a few weeks ago at the White House with representatives from U.S. companies such as Comcast Corp and advocacy groups such as the international nonprofit Internet Society to build solidarity.

"This is one of those circumstances where I think it's fair to say there's absolute unanimity. I don't believe you'd find any dissent at all to the view that we would like to keep the Internet free of inter-governmental controls," said a State Department official, who was not authorized to speak on-the-record about the discussions.

The Internet is currently policed loosely, with technical bodies such as the Internet Engineering Task Force, the Internet Corporation for Assigned Names and Numbers and the World Wide Web Consortium largely dictating its infrastructure and management. The United States holds significant sway with those bodies.

When the delegations gather in Dubai, they will renegotiate a UN treaty last revisited in 1988 and debate whether to consolidate control over the Internet with the UN's International Telecommunications Union (ITU).

The ITU is used to set communications standards, such as deciding when technologies can be labeled 4G and approving a standard for a universal telephone charger.

For many countries, it seems a natural progression for the ITU, formerly the International Telegraph Union in the 1800s, to morph into the International Internet Union in the 21st century. But for countries such as the United States the move is seen as dangerous.

The United States fears that authoritarian regimes will campaign for their initiatives by promising to back proposals from developing countries that would like to see tariffs on content-heavy Internet companies such as Google Inc and Facebook Inc.

"The votes of governments would be traded for considerations that have nothing to do with the Internet. That political horse trading is the hallmark of inter-governmental bodies," said Steve DelBianco, executive director of NetChoice, a coalition whose members include AOL Inc, eBay Inc, Facebook, Oracle Corp, VeriSign Inc and Yahoo Inc.

DIPLOMACY

The House panel said in a memo released on Tuesday that there is bipartisan agreement that the United States should stand firm in opposing any treaty provisions at the WCIT that would give the UN substantial control of the Internet.

"Pending international proposals to regulate the Internet could jeopardize not only its vibrancy, but also the economic and social benefits it brings to the world," the memo said.

The hearing will include testimony from Ambassador Philip Verveer, the deputy assistant secretary of state who will negotiate with other nations at the WCIT and help represent the United States in Dubai.

Vinton Cerf, regarded as one of the fathers of the Internet and now vice president and chief Internet evangelist at Google, and David Gross, the State Department's former ambassador for international telecom policy and now a partner at Wiley Rein, will also testify.

Gross, who is appearing on behalf of an industry coalition that includes Google, Microsoft Corp and News Corp, said in his prepared testimony that this is not the first attempt to centralize control over the Internet, pointing to UN talks in 2003 and 2005.

He said the United States must take a diplomatic approach that does not unnecessarily attack the UN's telecommunications authority, but instead concentrates on countries seeking to impose government mandates on the Internet through the UN.

Gross called for a strong coalition between the United States and like-minded countries.

"This has been done before and it must be done again," he added.