Former U.S. Senate candidate John James is seen as one of President Trump's top candidates to become ambassador to the United Nations, a source familiar with discussions about the matter told Fox News on Tuesday.

The source said James is the leading candidate and has expressed interest in the position to the White House. The belief among Trump's inner circle is that James is a rising political superstar, and the U.N. post could provide him with a pathway into elected office. White House officials also confirmed to Fox News that James is under consideration.

The 37-year-old James, a West Point graduate and veteran of the Iraq War, won the Republican primary for the Senate in Michigan last year but was defeated in November by three-term incumbent Democrat Debbie Stabenow. However, the race was unexpectedly close, and GOP officials in Michigan have expressed hope that James will challenge the state's other Democratic senator, Gary Peters, in 2020.

Michigan has not elected a Republican to the U.S. Senate since Spencer Abraham in 1994.

HEATHER NAUERT WITHDRAWS FROM CONSIDERATION FOR UN AMBASSADOR, STATE DEPARTMENT SAYS

Trump originally nominated State Department spokesperson Heather Nauert in December to replace Nikki Haley as U.N. ambassador. Nauert, a former Fox News anchor and correspondent, withdrew her name from consideration last week, citing "the best interest of her family."

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A State Department source told Fox News that the nomination process, on top of the demands of traveling around the world and between Washington and New York to see family, grew to be too much for her.

Since Haley's departure at the end of last year, career diplomat Jonathan Cohen has served as acting U.S. ambassador to the U.N.

Fox News' John Roberts contributed to this report.