GOP fight to replace McConnell turns ugly over immigration

The race to replace retiring former Senate Majority Leader Mitch McConnell (R-Ky.) has turned ugly over immigration.

Why it matters: The seat is safely Republican, but the primary is shaping up to be one of the cycle's most bruising intra-party battles.

Rep. Andy Barr (R-Ky.), former Attorney General Daniel Cameron and businessman Nate Morris are leading contenders.
Though none has secured President Trump's endorsement.

Driving the news: A Club for Growth-aligned super PAC, Win It Back, launched a new TV ad titled "Amnesty Andy" targeting Barr over immigration.

"In México, they call him Amnesty Andy and illegal aliens' best amigo," a narrator says in the ad.
In under a week, Win it Back PAC dropped nearly $750,000 on the spot, airing in Lexington, Evansville, Louisville and Bowling Green, according to AdImpact.
The group has also worked to paint Barr as closely aligned with McConnell, saying in another ad that he was "groomed" by the former majority leader.

The other side: Barr pushed back, saying in a statement: "Let's be clear: I never have and never will support amnesty."

"Win It Back is criticizing me for voting to support President Trump's plans to secure the border, build the wall, and enforce our laws. Just like President Trump said in Kentucky earlier this month, I've been with him all the way—and I always will be."
In one of Barr's recent ads titled "Cheers to ICE", he flexed his pro-immigration enforcement credentials, referencing how he supported expanding the number of ICE agents in the "big, beautiful bill."

Zoom out: The ad underscores how sharply negative the primary has become, with outside groups pouring millions into the race.

Elon Musk cut a massive $10 million check to bolster Morris earlier this year, the biggest single contribution he's ever given a Senate candidate.