Senate Democrats from energy-producing states blasted the Environmental Protection Agency’s proposal to rein in carbon emissions from power plants — but most of the party fell in line behind President Barack Obama’s biggest second-term domestic initiative.

“While it is important to reduce carbon in the atmosphere, this should not be achieved by EPA regulations,” Sen. Mary L. Landrieu, D-La., said in a release. “Congress should set the terms, goals and timeframe.”

Landrieu, who is in a tough re-election campaign, said she has long opposed taking on the issue through EPA regulation and stressed that she was a “key vote” that helped block efforts to establish a cap-and-trade system in 2010.

“Greater use of natural gas and stronger efficiency measures adopted by the industry have already helped us reduce carbon emissions to their lowest levels in 20 years, and this should continue,” Landrieu said. “I will work with leaders of both parties to build on the progress we have already made.”

Asked if Obama is concerned about political problems the rule could pose for coal-state Democrats, White House Press Secretary Jay Carney said, “The president thinks this is the right thing to do and it is consistent with actions taken to reduce pollution caused by lead or mercury, caused by arsenic.”

Sen. Joe Manchin III, D-W.Va., who famously shot the cap-and-trade bill in a TV ad in 2010, also criticized the proposed rule.

“There is no doubt that seven billion people have had an impact on our world’s climate; however, the proposed EPA rule does little to address the global problem with global solutions,” Manchin said in a statement. “Instead, today’s rule appears to be more about desirability rather than reliability or feasibility, with little regard for rising consumer prices, the effects on jobs and the impact on the reliability of our electric grid.”

Manchin noted that experts, including those at the White House, expect coal to provide nearly a third of our electricity through 2040.

“The EPA has proposed rules that are not based on any existing technology that has been proven on a commercial scale,” Manchin contended.

Sen. Heidi Heitkamp, D-N.D., was also cautious in her response, saying she is still looking at the rule.

“Today, coal produces 40 percent of the electricity in the U.S., and nearly 80 percent of the electricity in North Dakota,” Heitkamp said, “I’m still reviewing this extensive rule to determine the impact on the U.S. and North Dakota. We need policies that support coal — defending jobs, keeping energy costs low, and maintaining reliability in our electric grid — and that also help develop technology that is not yet widely available to reduce emissions.”

Sen. Mark Begich, D-Alaska, one of a group of vulnerable Democrats, kept a watchful tone.

“Today’s announcement from the Administration is the first step in a long process that I will be closely monitoring to determine any impact on Alaska — especially for consumers,” Begich said in a release. “Alaska is ground zero for climate change and there are common sense approaches to dealing with that reality, but we must protect consumers along the way.”

The draft proposal is subjected to a 120-day public comment period and will not be finalized until at least June 2015, noted Begich, who is also in a tight re-election race.

“From the initial review of materials released today, this rule exempts all of rural Alaska, but could impact a handful of Railbelt power plants,” Begich continued. “I will work closely with both the EPA and the State of Alaska to ensure that any final rule is flexible and protects Alaska businesses and families.”

Sen. Sherrod Brown, a Democrat who represents manufacturing-heavy Ohio, stressed that states need flexibility to address carbon emissions and climate change.

“Proposals to reduce climate change must give states the flexibility to increase energy efficiency, improve our air quality, and invest in clean energy technology at our power plants, homes, and businesses,” Brown said in an email from his office. “Ohio has already made strides in reducing carbon pollution thanks to fuel efficient cars, natural gas production, renewable energy, and highly efficient manufacturing facilities. I will closely follow this issue and work with industry and environmental leaders to ensure the final rule improves air quality while promoting continued economic growth.”

Sen. Mark Udall, D-Colo., another vulnerable Democrat, the rule was a “good start” and noted that Colorado has already taken steps to address the issue, including utilizing wind, solar and natural gas.

“Coloradans also have led the nation over the past decade in confronting this challenge and showing how we can reduce carbon emissions, protect our land, water and air, and strengthen our economy,” Udall said in a statement. “The EPA’s draft rule is a good start, and I will fight to ensure it complements the work we have already done in Colorado and provides states the flexibility they need to make it successful.”

Udall is in a re-election fight against Rep. Cory Gardner, R-Colo.

Meanwhile, most Senate Democrats embraced the EPA’s proposal, including Senate Majority Leader Harry Reid, D-Nev., who has long been critical of emissions from coal-fired power plants.

“The EPA’s proposed plan is a crucial step towards improving the efficiency of our nations power grid, investing in clean energy and reducing pollution,” Reid said. “The proposal grants states flexibility while making important progress on avoiding the terrible costs of carbon pollution on our nation’s economy, the health of our citizens, and the sustainability of our planet.”

Republicans were critical of the proposal and Senate Minority Leader Mitch McConnell, R-Ky., who is also up for re-election, has promised to try and block the rule.

“By imposing these draconian new rules on the nation’s coal industry, President Obama and every other liberal lawmaker in Washington who quietly supports them is also picking regional favorites, helping their political supporters in states like California and New York while inflicting acute pain on states like Kentucky,” McConnell said. “The impact on individuals and families and entire regions of the country will be catastrophic, as a proud domestic industry is decimated — and many of its jobs shipped overseas.”

McConnell has sought to make the “war on coal” an issue against his opponent, Alison Lundergan Grimes.

It was reported by various outlet that she has a fundraiser with Reid scheduled for Thursday morning in Washington, which prompted tweets over the fact that Reid is a coal critic, including this one from longtime Nevada political journalist Jon Ralston:

Allison Grimes: Don’t hurt KY’s coal industry. @SenatorReid: “Coal makes us sick.” Thursday: Reid-Grimes fundraiser. Any coal money there?

— Jon Ralston (@RalstonReports) June 2, 2014