For months, national Democratic operatives have been telling anyone who will listen — and there aren’t many such people in Washington – that embattled Dem incumbent Senators will beat back challengers, in spite of the difficult national political environment, by casting these races as a choice between two candidates.

That’s why Democrats are circulating this piece in the Arkansas Democrat-Gazette about the current state of the Senate race there. This is the sort of local political coverage to keep an eye out for as a test of whether Dems are making good on that vow.

The piece, by John Brummett, notes that Mark Pryor “should be losing” because of Obamacare. But he’s now ahead. Why? Because Pryor “has successfully made the race as much about his extremist opponent as about himself.” That opponent, Tom Cotton, “remains aloof and abrupt and unappealing,” and “wants to raise the age for eligibility for Social Security and Medicare to 70.”

This is notable because the Arkansas Senate race may be Exhibit A in the case that commentators might be getting it wrong in over-hyping the centrality of Obamacare (and more broadly the national environment) as factors imperiling Dem control of the Senate. Multiple prognosticators had written off Pryor as the pre-eminent Dead Dem Walking in the country, until polls showed Pryor leading. That prompted folks to start noting, as Chuck Todd put it, that “campaigns matter.”

Here’s another interesting example: The Iowa Senate race. Remember that ad in which GOP Senate candidate Joni Ernst whipped out a handgun and unloaded, while a narrator vowed she would “take aim at wasteful spending”?

Now the Associated Press reports that Iowa Republicans are worried that the trigger-happy spot — designed for a GOP primary audience — could alienate independents in the general election. The AP notes that this may not be quite the right posture to strike in an effort to replace retiring liberal Senator Tom Harkin:

It’s become a delicate balance for candidates: Convince the party faithful they have the conservative chops to distinguish themselves from the Senate’s longtime liberal lion, then turn around and face one of the nation’s most politically balanced statewide electorates in a general election that could determine which party controls the powerful chamber.

Also noteworthy: Ernst has flirted with climate skepticism and has backed a Personhood measure. It seems implausible to many that these issues could matter at all, since this election is supposed to be about All Obamacare All The Time, but Dem strategists continue to insist that such positions will be used to draw a sharp contrast with the extremism of GOP candidates — and in the process, turn these contests into choices between the candidates on the ballot.

It still seems clear that Republicans have at least a 50-50 chance of taking the Senate, in part because Dems are on defense — and are being forced to resort to this strategy — in so many Romney states. But it’s worth recalling that, while the parallel is far from perfect, many scoffed when Dems claimed they’d turn the 2012 presidential election into a choice between two candidates and visions, rather than merely allowing it to be a referendum on the Obummer economy. And that turned out to be right.

* OBAMA’S EPA RULES WILL GIVE STATES FLEXIBILITY: This will be the big battle of the summer. The Wall Street Journal has some new details about the coming EPA rules on existing power plants:

The proposal is designed to give states, which will administer the regulations, flexibility to meet the [carbon emission] benchmarks, as opposed to placing emissions limits on individual plants, according to people familiar with the Environmental Protection Agency’s work on the rule.

Central to the strategy of flexibility: the option to include a cap-and-trade component where a limit is set on emissions and companies can trade allowances or credits for emissions as a way of staying under different benchmarks the EPA sets for each state.

Obviously, no matter how the EPA rules are designed, they will be portrayed by Republicans as equal parts federal tyranny and Big Gummint wet blanket on the economy.

* THE COMING WAR OVER CARBON: To understand the above, see Jonathan Cohn’s comprehensive primer on all the ins and outs of the coming EPA regulations, including how to tell whether the rules are ambitious enough to have the impact required, and a look at the parameters of the legal and political battle that is set to unfold.

If Obama opts for the most ambitious type of rules — a so-called “system-wide” approach that includes targets for carbon reduction but also efforts to reduce electricity consumption — that would make success at reductions more likely. But it would also arouse the most opposition from Republicans, industry and possibly the courts, which is inevitably where this will all get settled.

* WORLD GOVERNMENTS WATCHING OBAMA ON CLIMATE: Coral Davenport reports that governments from Beijing to Brussels are watching closely to see just how ambitious Obama’s coming new rules on existing coal-fired power plants will be, which will provide a sign of whether international cooperation to curb carbon emissions will be truly possible.

Obama’s regulations will lay the groundwork for U.S. participation at a coming United Nations summit whose goal is a treaty to be signed next year legally binding major countries to new carbon standards — the latest sign that this battle may matter more than anything else to Obama’s legacy.

* REPUBLICANS AND VETERANS GROUPS AT ODDS: The New York Times reports that Senator Richard Burr is attacking veterans groups because they have failed to call for the ouster of VA chief Eric Shinseki, but those groups are now turning on Burr, enraged that he won’t support the broader approach to veterans’ health reform that they prefer.

The larger battle here — over whether the proper reforms should turn on maximizing competition with private care, as Republicans want – will likely now come to the fore, and as the Times story notes, it’s unclear whether this will reflect well on Republicans, because veterans groups say private care can’t provide the kind of services needed.

* GOP EVASIONS ON OBAMACARE CONTINUE: I’m late to this, but you know I have to take note of it. Mitch McConnell is now saying, laughably, that the fate of Kentucky Kynect is “unconnected” to his continuing insistence that we must repeal Obamacare.

It’s worth noting, again, that multiple Republican Senate candidates are evading core questions about Obamacare repeal and the Medicaid expansion in their states. Much of what they are spouting is outright gibberish, yet it’s attracting little attention from the national media, while evasions by Dems like Alison Lundergan Grimes and Michelle Nunn are (rightly) treated as highly newsworthy.

* HOW LANDRIEU HOPES TO WIN REELECTION: The Post’s Philip Rucker has an interesting look at how Landrieu hopes to win by emphasizing her record in delivering for the state and her ascension to chair of the Energy Committee:

Landrieu’s advisers argue…she has a well-established reputation of fighting on Louisiana’s behalf — most prominently to direct federal disaster aid in the wake of Hurricane Katrina in 2005. And they say their research shows that the oil and gas industry is so central to people’s economic security here that once everyday voters inclined to turn out Landrieu are reminded of what she has done and could do for the state, they’ll think twice. That’s why Landrieu is traveling the state showing the power of her post.

Vulnerable Dems are relentlessly grounding their candidacies in the states, to shift the campaigns away from long-running Washington arguments, such as the one about Obamacare. For Landrieu, the Medicaid expansion being debated in Louisiana is key to localizing the health care argument.

 * AND THE QUOTE OF THE DAY, OBAMACARE DERANGEMENT EDITION: This suggestion as to the real GOP attitude towards the continuing standoff over the Medicaid expansion in Virgina, from Senator Tim Kaine, is worth thinking about:

He said Republicans in Virginia want it to happen, but don’t want to have to be responsible for the vote. “I actually think there are some who would actually rather he do it in an executive way,” Kaine said. “They want it to happen but they don’t want to vote for it to happen and they’d rather he do it.”

After all, what’s a GOP lawmaker to do, when the base refuses to let you support bringing in billions of dollars to expand coverage to hundreds of thousands?

Greg Sargent writes The Plum Line blog, a reported opinion blog with a liberal slant -- what you might call “opinionated reporting” from the left.