Republican Rep. Thomas Massie faces the toughest fight of his career, positioning himself as the only GOP candidate centered on defying President Trump. The Kentucky libertarian has become a thorn in Trump's side on issues from federal spending to Iran war, earning labels of "disloyal" from the president.

More than $5 million has flooded the race from outside groups, including the Republican Jewish Coalition and three GOP megadonors, making this the most expensive congressional primary in the nation. Trump personally endorsed challenger Ed Gallrein, who campaigned as a loyal Trump ally with a "big, beautiful brain."

Massie embraces his role as an independent voice, reminding voters that "in Congress, we don't report to the president." While some supporters shifted allegiance following Trump's endorsement, Massie maintains his principled stance, betting constitutional principles will resonate with voters in the May 19 primary.