Once Stefanik vacates her seat, the 21st District must hold a special election within 90 days — meaning the seat could stay empty until as late as April.

Stefanik serves as House Republican Conference Chair and has long been one of Trump’s most loyal allies in the House.

President-elect Donald Trump will nominate Rep. Elise Stefanik, R-N.Y., for the U.S. ambassador to the United Nations, he confirmed to the New York Post on Sunday night, making her third key pick Trump has formally announced for his upcoming administration.