In states where nearly all of the electricity is generated by coal, like West Virginia and Kentucky, Democrats were quick to denounce the plan, which they fear would cost jobs.

　　Alison Lundergan Grimes, who is challenging Senate Minority Leader Mitch McConnell, immediately distanced herself from the plan and from the White House, saying she would — quote — "fiercely oppose the president's attack on Kentucky's coal industry."But a recent Washington Post/ABC News poll found 70 percent of Americans actually support curbing greenhouse gas emissions.

　　Joining us for a look at how the decision is resonating politically are Susan Page of USA Today and Reid Wilson of The Washington Post.

　　Sue, let's draw this coal map for us. Does it completely mirror the battleground map we have been watching?

　　SUSAN PAGE, USA Today: It mirrors a lot of the key states where there are competitive Senate races, control of the Senate at stake in November, states like West Virginia, Arkansas, Kentucky, Louisiana, Colorado.

　　These are states where most of the electricity is generated by coal-fired plants. This may not be a big controversy in the some states in this country, but it's a big controversy in the states on which control of the Senate now hinges.

　　GWEN IFILL: So, is this a regional issue or a national issue, Reid?

　　REID WILSON, The Washington Post: Well, it's a regional issue. A lot of states on the coast, specifically in the Northeast, have actually curbed carbon emissions quite a lot.

　　The plan by the EPA requires states to curb emissions to a rate 30 percent less than what they were emitting in 2005. A number of states have actually already met that particular goal. The problem is, it's not in that Rust Belt section, Midwest America, where coal is still a huge portion of the state's energy concerns.

　　GWEN IFILL: Is the concern, Susan, about jobs, mines that would close, or is it about the idea of federal intervention?

　　SUSAN PAGE: It's about both.

　　And the federal intervention argument I think works particularly well for opponents of this plan, because the president didn't do this through legislation that passed Congress, because he wasn't able to get that legislation through Congress. He's doing this through executive action, regulations at a federal agency, so that fuels the idea, as with the health care plan, that it's a federal mandate on the states.

　　But the argument about jobs is also, I think, an incredibly powerful one in states like Kentucky, which is probably the highest — you know, the Senate race we're looking at closely because the future of the leading Republican senator is at stake there. That — and the jobs argument is also a powerful one.

　　GWEN IFILL: There are some leading Democrats who also are facing a pretty tough race in some coal states. And I'm thinking about Mary Landrieu, for instance, in Louisiana.

　　REID WILSON: Mary Landrieu has made her influence on the Senate Energy and Commerce Committee, where she is the chairwoman, a central part of her campaign. She is very pro-drilling. She's pro-fracking, in favor of coal mining. Basically any energy proposal that you can come up with, she will back it.

　　Just last week, she took the secretary of energy around Southern Louisiana. She's trying to tell voters that she is going to be a pro-energy Democrat. Now more and more voters, though, are voting based on the letter at the end of her name, whether it's a D or an R, than her actual policy proposals in the first place. So that is going to be a difficult challenge for her as she faces one of the toughest reelections of any candidate running for reelection.

　　GWEN IFILL: Take us to West Virginia and Alaska, two other states where this is playing out.

　　SUSAN PAGE: West Virginia is a state where the incumbent Democrat is retiring, Senator Rockefeller.

　　We have two women candidates, two strong women candidates. They're both very much opposed, they say, to this plan. But one of them is a Democrat. One of them is…GWEN IFILL: Natalie Tennant, yes.

　　SUSAN PAGE: … in the same party as — Natalie Tennant, the secretary of state.

　　And so, despite her efforts to distance herself from President Obama, this does — it's hard for her to totally argue that she's not a Democrat, even though she differs with the president on this issue.

　　GWEN IFILL: And Mark Begich in Alaska faces the same problem. And he's an incumbent.

　　So, why then does the White House rub salt into the wound on this issue? Why make it so hard for Democrats especially?

　　REID WILSON: I think it's in large part because President Obama hears the clock ticking.

　　He doesn't have that long left in office. He's only got two-and-a-half years until his successor takes over. If he doesn't put in this rule now, if he doesn't start the implementation process, the rule won't be finalized by the time he leaves office.

　　If a Republican president is the next one in, they can scrap this rule before it has taken effect. Remember, President Obama's 2008 acceptance speech at the Democratic Convention, he said, this would be the time when the planet starts to heal. This is the most aggressive step that any president has taken on climate change so far, but it's a step that clearly puts his party and very vulnerable members seeking reelection at odds with some voters who are going to determine the outcome of the U.S. Senate.

　　GWEN IFILL: And yet the words climate change didn't show up much in this announcement. It was all about health and children's asthma concerns and it was — and jobs.

　　SUSAN PAGE: Because those are the — those are the words that poll better. Those are the words that appeal to a broader range of voters.

　　When you talk about climate change, it's an issue that appeals very much to some voters, but really turns some voters off. And that's why you heard him talk about other aspects of this program, not calling it climate change. But I certainly agree with Reid.

　　The president is thinking about his legacy. Could his legacy be dealing with an issue that he talked about so much in the 2008 campaign, like climate change, or could it be holding the Democratic Senate? You give him that choice, I think he would take climate change every day.

　　GWEN IFILL: But if you Jeanne Shaheen in New Hampshire, or Kay Hagan in North Carolina, or Mark Udall in Colorado, wouldn't you like his legacy to be a Democratic Senate?

　　SUSAN PAGE: Well, look at those races you named.

　　Now, there's an interesting test, because they are not taking the same tack as we're seeing in Kentucky and West Virginia. Mark Udall in Colorado, who is in a very competitive race, is saying we need to do things like this, we need to address climate change. So is Jeanne Shaheen.

　　Kay Hagan in North Carolina in a very close race is saying, we need some balance. So, we will have a test in November about whether this issue is devastating for Democrats or whether it's one that can — where the needle can be threaded.

　　GWEN IFILL: Is it also one of those issues where there's a lot of money coming from outside these states into — for instance, we saw there is some very pro-environmental money coming into these states on these issues, as well as anti.

　　REID WILSON: Donors who care a lot about climate change are becoming an increasingly large part of the Democratic primary, the Democratic sort of money pool, if you will, led by a billionaire in California named Tom Steyer, who has pledged $100 million of his own money for some key races, including the races that you just mentioned in New Hampshire, in North Carolina, and in Colorado.

　　And the difference between what we have seen in the past and what we're going to see now is in the past, people who cared a lot about climate change talked about global warming and the rising of the seas and polar bears falling in the water in the Arctic and all this. And now what they are going to talk about is drought in Iowa and floods in North Carolina and the sort of immediate, everyday impact.

　　Public health is going to be a huge part of it, whether or not your children have asthma. They are going to try to connect climate change to our everyday lives, to everybody's pocketbook issues, if you will, and try to make it resonate on a much more personal level than they have in the past.

　　GWEN IFILL: And when we stop and think about it, it's not really all that unusual for Democrats to be running against Democratic or Republicans running against Republican presidents in midterm elections.

　　SUSAN PAGE: It's true.

　　But we also know that the popularity of the president is a big factor in a midterm election, especially a six-year midterm. President Obama is stuck in the low 40s, and that's very bad news for these Democrats in competitive races.

　　GWEN IFILL: Susan Page, Reid Wilson, thank you both very much.

　　REID WILSON: Thank you.

　　SUSAN PAGE: Thank you.