A Federal Communications Commissioner blasted supporters of the government’s plan to hand over oversight of key internet functions to the international community Tuesday, saying the threat of influence and censorship by oppressive regimes is real.

Commissioner Michael O’Rielly, one of the FCC’s two Republicans, said the Obama administration’s plan to relinquish oversight of the Internet Corporation for Assigned Names and Numbers (ICANN) — the organization that manages the internet’s Domain Name System — presents a real threat to the free flow of information online.

“I have grave concerns that one or more foreign governments would be able to unduly influence or control the new ICANN,” O’Rielly said in a speech. “This transition is a serious undertaking, and once done, it cannot be undone.”

The transition, scheduled to take place on Oct. 1, would end the Commerce Department’s 18-year oversight of ICANN, which manages crucial back-end function of the internet like assigning internet protocol addresses, overseeing domain names like .com and .org and running the root servers that route web addresses to their correct source.

Republicans have been skeptical of the plan since it was announced in 2014, many suspect as a concession to the international community over the leak of global digital surveillance programs leaked by former National Security Agency contractor Edward Snowden. They’ve stalled the transition for the last two years with appropriations riders pushing it back, the latest led by Texas Republican Sen. Ted Cruz.

Democrats and ICANN officials say the transition has been planned since the 1990s, and have dismissed critics’ concerns of online censorship as talking points by politicians with little to no understanding of ICANN’s role, which they argue has never included a mandate or authority to protect free speech online.

“We should also dispense with the notion that the IANA [Internet Assigned Number Authority] functions are merely perfunctory or meaningless. If that is the case, then why is there even a dispute or a demand that the U.S. ‘relinquish control’?” O’Rielly said.

“While some may assert that opponents of the transition are individuals who don’t understand fundamentally what is at issue, this is far from the truth,” he continued. “We understand that the underpinnings of the internet are being put at risk because of other global policy debates and a desire to conclude this process prior to the election.”

The commissioner said there’s no disputing other government’s will have a larger influence over ICANN, since the Government Advisory Committee (GAC) established under the plan will give countries including Russia and China a seat at the table equal to the U.S.’s, though they’ll have to agree unanimously on advice they pass on to the board of private companies and technical organizations that will directly oversee ICANN.

However, the GAC can also participate in votes with the “empowered community” (so long as the votes aren’t on GAC proposals), providing “the GAC with votes over such fundamental decisions as dismissing the board and individual directors and bylaw changes.”

O’Rielly said ICANN’s commitment to “internationally recognized human rights” and the lack of consensus among states about what those norms are “could enhance the ability of authoritarian regimes to use ICANN’s functions to control and sensor content.”

“Certain domain names and IP addresses could be refused, turned off or traffic diverted if the websites contain content that some find objectionable,” he said.

Eventually, he warned, the lack of U.S. control and pressure from other countries could lead to a vote to transition ICANN’s functions to the United Nations’ International Telecommunications Union or the U.N. itself, where regimes like China and Russia would have more influence.

“Is the global internet community able to discipline the board to prevent abuse or undue influence?” O’Rielly asked. “Left unresolved, this entire Jenga-like structure could easily crumble, bolstering efforts for additional government involvement in Internet operations.”

“Many consider it a small price to pay for other government activities, like those revealed by Edward Snowden. But, the Internet isn’t something that should be compromised as a means to assuage critics or meet artificial deadlines.”

Last week, lawmakers asked FCC Chairman Tom Wheeler to weigh in — an invitation he politely declined.

“That’s a matter that’s in the Department of Commerce and I’m glad of it,” Wheeler said during an FCC oversight hearing in the Senate. “It is not in my remit.”

A rider to delay the transition for the third year in a row is one of the sticking points lawmakers are debating in a continuing resolution to fund the government from October to December, when Congress will return from election campaigning to work out a long-term agreement.

Follow Giuseppe on Twitter