Nick Adams, known for his crass humor and internet trolling, was previously nominated to be the ambassador to Malaysia. But his nomination was pulled earlier this year.
Parties normally hold conventions every four years to nominate presidential candidates, but Republicans hope to hold one this year in the face of midterm headwinds.
A day after President Trump said he did not want a compromise, Republicans were exploring breaking off ICE funding so the rest of the Department of Homeland Security could reopen.
The Republican congressman from Kentucky is a die-hard libertarian who has centered his campaign on his willingness to buck the president. It has bought him the most expensive primary in the country.