Alison Lundergan Grimes has released a radio ad criticizing President Barack Obama for his "pie in the sky" power plant regulations.
The ad, which claims the new regulations will hurt the commonwealth, debuted Wednesday in coal regions in eastern and western Kentucky.
Grimes says in the ad that Obama's plan will lead to utility rate increases, shortages of power and the loss of more coal jobs.
She says it's clear Obama has "no idea" how his plan affects the state.
The ad is a response to Obama's plan to order big cuts in pollution discharged by power plants.
It represents Grimes' latest attempt to distance herself from Obama, who is unpopular in Kentucky.
She is challenging Senate Minority Leader Mitch McConnell in the fall election.
McConnell campaign spokeswoman Allison Moore says the ad is "transparently political."