Editor's note: This story has been updated throughout.

Texas Attorney General Ken Paxton is jumping into Ted Cruz's fight to stop what the U.S. senator calls President Barack Obama's illegal internet "giveaway."

Paxton and three other attorneys general filed a lawsuit Wednesday night aiming to halt the Obama administration's plan to cede oversight of the internet domain-name system to an international body. Critics claim the transition, which is set to go into effect within days, could open up the Internet to censorship by countries like China and Russia.

"Trusting authoritarian regimes to ensure the continued freedom of the internet is lunacy," Paxton said in a statement. “The president does not have the authority to simply give away America’s pioneering role in ensuring that the internet remains a place where free expression can flourish."

The lawsuit argues that the transfer, among other things, violates the property clause of the U.S. Constitution by letting go of government property without Congress' approval. It also says the plan will have a negative impact on Americans' free-speech rights under the First Amendment.

A spokesperson for the National Telecommunications and Information Administration, one of the defendants, did not immediately respond to a request for comment. But administration officials and technology experts have said concerns like those raised by Cruz are unfounded and demonstrate a lack of understanding about how the internet works.

The transfer has been years in the making, with the United States looking to relinquish control over domain-name registration to an international nonprofit known as the Internet Corporation for Assigned Names and Numbers. The transfer is scheduled to go into effect Saturday.

In Congress, Cruz has made stopping the transition his top priority since returning from the presidential campaign trail in May. His efforts, however, have largely stalled, especially after Congress passed legislation Wednesday that will keep the federal government open through mid-December. That bill did not address the internet issue, as Cruz had hoped.

Cruz and Paxton, both tea party favorites in Texas, have long been allies in fights against the federal government. The three other attorneys general joining Paxton in the lawsuit are Mark Brnovich of Arizona, Scott Pruitt of Oklahoma and Paul Laxalt of Nevada.

In Congress, Cruz has made stopping the transition his top priority since returning from the presidential campaign trail in May. His efforts, however, largely stalled after Senate Majority Leader Mitch McConnell unveiled a spending bill last week that did not address the issue.

The three other attorneys general joining Paxton in the lawsuit are Mark Brnovich of Arizona, Scott Pruitt of Oklahoma and Adam Laxalt of Nevada.

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