In a speech last night, embattled Senator Kay Hagan blasted GOP challenger Thom Tillis over his climate denialism, arguing that North Carolina “needs a Senator who believes climate change exists.” Hagan added: “Unlike my opponent who flatly denied the existence of climate change, I know the EPA’s ability to responsibly regulate greenhouse gas emissions is key to protecting our environment for future generations.”

However, Hagan has also called on the EPA to delay the introduction of pending new rules on carbon emissions from existing coal-fired power plants, something Tillis has tried to turn into an issue.

The two moves aren’t necessarily contradictory — Hagan says we need a longer public comment period for those who will be impacted, not that there shouldn’t be any new rules — but they do underscore that embattled Senate Dems may find themselves in a tricky political position when Obama rolls out the new rules next week.

This is also the latest sign climate change could actually become something of an issue in this year’s campaigns, something environmentalists have long hoped for.

Obviously climate change will not be a central issue in Senate races. But the topic will probably get more attention than usual. In part, that’s because more GOP candidates appear to have dabbled in climate skepticism. Among them: Tillis, Terri Land in Michigan, Cory Gardner in Colorado, and Joni Ernst in Iowa.

Dem Rep. Gary Peters, who is running for Senate in Michigan, has already begun to make an issue of Land’s climate skepticism in Michigan, in part because of climate change’s potential impact on the Great Lakes. Meanwhile, billionaire environmental activist Tom Steyer has vowed to spend $100 million highlighting GOP climate denialism, singling out Land, Gardner, and Ernst.

A Michigan newspaper is reporting that Land hit Peters today, accusing him of standing with a “billionaire radical from California.” (There’s no mention in the report of whether Land has yet clarified her climate skepticism.) The flip side of this, of course, is that Democrats can use the issue of climate change to draw more attention to the Koch brothers’ efforts to elect Land and other Republicans to the Senate.

Indeed, the massive Koch expenditures are another reason climate change may draw more attention this year: As Forbes has noted, Koch industries has “contributed millions to organizations that have studied human-induced global warming with skepticism,” raising questions about “whether their political activities are blatantly self-interested,” given that Koch Industries is “a major carbon emitter, vulnerable to tighter emissions controls.”

Dems will likely point to the Koch brothers when the next big climate change-related political issue flares up: those new EPA rules. Even as the Kochs spend tens of millions of dollars to transfer the Senate to Republicans, with the explicit goal of persuading Americans that the answer to their economic problems is fewer government regulations (such as environmental regs), the campaign arm of Senate Republicans is set to use the new EPA rules to put embattled Dems in a tough spot, by casting those rules as the latest in Job Killing Obummer Big Gummint. An NRSC email to reporters blasts red state Dems as follows:

What’s the point of them being there if their mere presence enables President Obama to implement his radical agenda by fiat? The short answer is that there is no point. They are powerless and useless.

Senate battleground states are largely coal-intensive states, which makes President Obama’s upcoming EPA announcement even more important….These states will be particularly hard hit by the rate spike that will come from the Obama administration’s energy fiat.

As I reported the other day, strategists acknowledge vulnerable Dems will have to deal with this issue, and you should probably expect some Dems — particularly in places like Kentucky and Louisiana — to distance themselves from the new rules. Hagan’s handling of it suggests some Dems will try to balance caution about their economic impact with an acknowledgment of the need for the rules, thus enabling them to call out their opponents’ climate denialism.

But however this ends up playing, climate change may now get more debate than usual in the context of hard fought political races, which is itself a step forward.