FIRST ON FOX: Under the U.S. Constitution, anyone who is not a "natural-born citizen" is barred from becoming president or vice president.

Now, a House Republican wants to expand that requirement to much of the federal government.

Rep. Nancy Mace, R-S.C., plans to introduce a joint resolution Wednesday proposing a constitutional amendment requiring members of Congress, federal judges and other Senate-confirmed appointees to be natural-born citizens.

The proposal would affect more than a dozen naturalized citizens currently serving in Congress, including several Republicans.

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Mace, who is running to be South Carolina’s next governor, suggested that the country’s nearly 25 million naturalized citizens, who made the deliberate choice to become Americans, may have divided loyalties.

"If you hold power in the American government, you should be a natural-born American citizen," Mace told Fox News Digital in a statement. "For too long we have allowed foreign-born members to hold seats in this government, while making clear their loyalty is not here. We see it every day."

Mace specifically called out progressive Rep. Ilhan Omar, D-Minn., who was born in Somalia and became a naturalized citizen in 2000.

"Ilhan Omar is just one of many foreign-born members of this government who have made clear, time and again, their loyalty is not here," Mace said. "The American people deserve leaders who put America first. This amendment closes a gap in our Constitution long overdue for closing."

Omar’s path to U.S. citizenship has also faced heightened scrutiny from Republicans in recent months. 

Vice President JD Vance said Tuesday that Omar is under investigation by the Department of Justice for possible immigration fraud. Some Republicans have called for her deportation over the alleged offense.

A spokesperson for Omar did not immediately respond to a request for comment.

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Mace’s proposal faces steep odds of becoming part of the Constitution, requiring a two-thirds vote in both chambers of Congress before ratification by three-fourths of U.S. states. Amendments can also be proposed through a constitutional convention requested by two-thirds of state legislatures, though that method has never been used successfully. 

There are 19 foreign-born members of Congress, though some are natural-born citizens due to having at least one parent who is a U.S. citizen.

Under Mace’s proposal, Sen. Bernie Moreno, R-Ohio, an ally of President Donald Trump who was born in Colombia and became a U.S. citizen at 18, could no longer serve in Congress. 

The same restriction would apply to Reps. Juan Ciscomani, R-Ariz., Young Kim, R-Calif., and Victoria Spartz, R-Ind., who became naturalized citizens after immigrating to the United States from Mexico, South Korea and Ukraine, respectively.

On the Democratic side, Reps. Pramila Jayapal, D-Wash., Ted Lieu and Robert Garcia, D-Calif., and Raja Krishnamoorthi, D-Ill., are among the lawmakers who would be affected.

Former Trump Transportation Secretary Elaine Chao, the wife of Sen. Mitch McConnell, R-Ky., and Alejandro Mayorkas, former President Joe Biden’s Department of Homeland Security secretary, also would have been ineligible to serve in cabinet posts under the proposal.