President Donald Trump reserved his fiercest attacks for Massie, a quirky conservative who had become among the most powerful rank-and-file Republicans in the House because of his willingness to vote as he pleased, rather than as the party demanded.

The Kentucky Republican has emerged as perhaps the president’s most critical primary target after bucking him on issues ranging from budget legislation to the Epstein files.

Rep. Thomas Massie will face off on Tuesday against a Trump-backed candidate in a Republican primary in Kentucky's 4th congressional district.