With the EPA's proposed new power plant rules posing a potential threat to Democrats running in coal-reliant states, Alison Lundergan Grimes is fighting back early -- and fiercely -- by attacking the president and the EPA in a new radio ad, unveiled Wednesday.

In the ad, which will air mainly throughout Kentucky's coal counties in the east and west of the state, Grimes takes President Obama to task for the new regulations on carbon emissions, which would be phased in over the next 15 years.

"Mr. President, Kentucky has lost one-third of our coal jobs in just the last three years," Grimes says in the ad. "Now your EPA is targeting Kentucky coal with pie-in-the-sky regulations that are impossible to achieve."

"It’s clear you have no idea how this affects Kentucky," Grimes adds.

The message is consistent with the pro-coal stance Grimes has taken so far in this election, if more pointed. In Kentucky, support for the coal industry, by far the state's biggest producer of energy, has long been bipartisan.

But Grimes' Republican opponent, Senate Minority Leader Mitch McConnell, has sought to make coal a wedge issue by tying Grimes to the Obama administration's environmental policies. He has also touted his own record of defending the industry, most recently with his proposed Coal Country Protection Act, which would prevent the new regulations from taking effect until the administration could guarantee no negative effect on jobs.

After Grimes' campaign unveiled its radio ad Wednesday, McConnell's campaign quickly panned Grimes' message as "belated."

"Her belated concern about the war on coal now that she's a candidate, after helping to ensure it by backing Obama, is insulting and transparently political," said Allison Moore, a spokeswoman for McConnell.

The match-up between McConnell and Grimes is among the most heated this year, with public polls consistently showing the two candidates in a statistical tie.