Just one day after the Environmental Protection Agency unveiled new carbon emissions rules for power plants, the National Republican Senatorial Committee will try to capitalize on the announcement with robocalls attacking Democratic candidates in four states.

The calls, which will begin Tuesday and target Sens. Mark Begich of Alaska, Mark Udall of Colorado, Mark Warner of Virginia, and Mary Landrieu of Louisiana, could be a sign of political attacks to come on Democrats. Invoking the EPA's new rules, the calls attempt to link Democrats to broader, unrelated environmental regulations proposed or imposed during President Obama's administration.

Calls targeting the first three senators will try to associate the new regulations with “cap and trade” — a term, used widely to describe a different proposal for curbing pollutants that cause acid rain, with which many Americans are still unfamiliar but that does not sit well with many Republicans.

“It’s not surprising Mark Warner stands by Obama’s costly regulations, because he stood with liberal senators in support of a plan that would have imposed a radical cap-and-trade plan on Virginia,” one of the calls will say.

The NRSC’s attack on Landrieu — who said Monday that Congress, not the EPA, should hold the authority to set emissions caps — takes further liberties, attempting to tie Landrieu to the new regulations via her support for other Democrats.

“Why has Mary Landrieu given hundreds of thousands of dollars to anti-energy Democrats? Landrieu even claims that she and Harry Reid are a team, even though Reid says ‘Oil makes us sick'?” the robocall says. “Tell Mary Landrieu that this war on American energy just doesn't make sense for Louisiana.”

Landrieu was part of a bi-partisan group of 45 senators that last month signed a letter asking that the EPA extend a public comment period on the new power plant rules.

The lawmakers got what they wanted, and the public will be allowed 120 days, double the normal 60 days, to weigh in on the new regulations on carbon emissions, unveiled Monday.

But vulnerable Democrats still face a complicated political outlook in light of the changes, not least of all because many of the frontline Senate races this year are in states uniquely reliant on coal.

In West Virginia and Kentucky in particular, ground zero for two major Senate races and where more than 90 percent of energy comes from coal, the federal government's "war on coal" has been a popular theme for candidates of both parties. Democrats Natalie Tennant in West Virginia and Alison Lundergan Grimes in Kentucky have insisted they would fight against further regulations on the industry.

"When I'm in the U.S. Senate, I will fiercely oppose the President's attack on Kentucky's coal industry because protecting our jobs will be my number one priority," Grimes, who is challenging Senate Minority Leader Mitch McConnell, said in a statement Monday.

But Republicans will aim to cast a pall over that message in light of the EPA's new rules, which a Democratic majority in the Senate did not slow in spite of misgivings among some of the party's senators about the administration acting unilaterally.

"For years, Democrats like Mary Landrieu, Mark Begich and Mark Warner have insisted that their influence within the Democratic ranks was reason alone to support their reelection bids," said NRSC spokeswoman Brook Hougesen. "Now, five months prior to the most difficult election of their careers, President Obama is turning a blind eye and a deaf ear to their concerns. An uphill climb just got even more difficult."

Landrieu, a Louisiana Democrat who recently took the gavel on the Senate Energy Committee, has touted her power to “deliver for Louisiana" on energy issues. But Republicans will likely try to flip that message on its head: Landrieu and others, Hougesen added, "all claim to be independent Democrats who stand up to President Obama, yet it turns out they are completely ineffective, and we will be reminding voters of that throughout the summer and fall."

Any political boost for Republicans could be limited, however, by broad public support for restrictions on carbon emissions. A Pew Research Center survey last year found support from 65 percent of Americans for stricter rules — a change favored by more than half of Republicans surveyed, too.

Democrats in battleground, but non-coal-heavy states, as a result, have been careful to attack what they view as overreach by the EPA without undermining the new rules themselves.

“While it is important to reduce carbon in the atmosphere, this should not be achieved by EPA regulations,” Landrieu said in a statement. “Congress should set the terms, goals and timeframe.”