A new Washington Post/ABC News poll finds Obama’s approval rating at 46-51, a finding that will draw every bit as much media attention as did last month’s poll showing his approval at 41 percent. (Okay, that isn’t really going to happen.) It also finds Dems lead the Congressional ballot matchup by 47-45, though that’s way too small to help Dems, given the deep structural disadvantages they face.

Indeed, this poll once again provides a glimpse of those structural disadvantages: It finds that the percentages of voters from core Dem groups who say they’re definitely going to vote are significantly lower than the percentages from core GOP groups who say the same. Overall, 74 percent of registered voters are absolutely certain to vote, and here’s the breakdown:

– 81 percent of Republicans are absolutely certain to vote, versus 74 percent of Democrats.

– 86 percent of conservative Republicans are absolutely certain to vote, versus 79 percent of liberal Democrats.

– 77 percent of white voters are absolutely certain to vote, versus 67 percent of non-whites.

– 79 percent of those over 65 are absolutely certain to vote, versus 66 percent of those from 18-39.

The poll also explains why Dems are placing so much of an emphasis on female voters:

– Dems lead among women in the generic ballot match-up by 52-42, while Republicans lead among men by 49-40. And yet…

– In the one seeming break from the above pattern, 77 percent of female voters are absolutely certain to vote, versus 70 percent of men.

The usual caveats apply: Some question how accurately such polls really predict voter behavior, and this is only one poll (though others have shown similar problems for Dems). Still, Dems themselves agree that they face what Ed Kilgore has called the “midterm dropoff problem,” and they are investing at least $60 million in doing something about it.

Economic populism is often derided as a Dem “base play,” to use that awful Beltway cliche. But the Dem emphasis on pay equity, the minimum wage hike (which is geared towards downscale women) and women’s health issues such as Personhood is very much about persuasion — about winning over women who might lean Republican — as it is about giving members of the Rising American Electorate (unmarried women, young voters, minorities) a reason to vote. As Sasha Issenberg detailed in his seminal piece on this topic, Dems’ only hope to offset deep structural disadvantages is a combination of persuasion and mobilization, i.e., the sheer grunt work of contacting voters again and again and urging them out to the polls.

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* AMERICANS SUPPORT BENGHAZI PROBE: Also from the Post/ABC poll: Americans support an additional Congressional probe into the administration’s handling of Benghazy by 51-42, and Americans believe the administration is covering up facts about Benghazi by 58-32.

Also, Americans disapprove of Hillary Clinton’s handling of the incident by 50-37. Whether or not this constitutes a “mandate” for the Benghazi probe, Republicans will likely interpret it as one.

* BIG GOP PRIMARIES SET FOR TODAY: As NBC’s First Read crew spells out (no link yet), today’s biggest election is the Mississippi GOP Senate primary, in which Tea Partyer Chris McDaniel is gunning for longtime incumbent Thad Cochran, setting up a possible Richard Mourdock redux with potentially huge ramifications for this fall:

Like Murdoch in Indiana, McDaniel appears prone to making a mistake…and just like in Indiana when Democrats had a credible nominee in Rep. Joe Donnelly to take advantage of any opening, Democrats don’t have a bad candidate in former Rep. Travis Childers…if Democrats get any kind of opening in Mississippi, here’s why that would be very important in November: A Democratic win there — as remote as it may seem — would raise the GOP’s magic number (from six to seven) in the seats it must net in order to win back the Senate.

Also keep an eye on Iowa, where gun-wielding, hog-castrating Joni Ernst is likely to win the GOP nomination, again casting doubt on the degree to which the “GOP establishment” has vanquished the Tea Party. She is the GOP establishment candidate, yet she has dabbled in climate skepticism and support for Personhood measures.

* BATTLE OVER BERGHDAL CONTINUES TO RAGE: This morning, Obama defended the decision to bring him home:

“We have consulted with Congress for quite some time about the possibility that we might need to execute a prisoner exchange in order to recover Bergdahl,” Obama said on a trip to Poland to discuss Eastern European security. “We saw an opportunity, and we were concerned about Bergdahl’s health. We had the cooperation of the Qataris to execute an exchange and we seized that opportunity.” He added that “the process was truncated because we wanted to make sure we would not miss that window.”

Meanwhile, the New York Times weighs in with a detailed accounting of Berghal’s conduct, noting that Pentagon officials are claiming some of the charges against him are unsubstantiated.

* ENERGY COMPANIES CAN LIVE WITH NEW EPA RULES: The New York Times talks to officials in the energy industry and finds that some of them aren’t all that worried about the new EPA rules, and indeed in some sectors they pose something of an opportunity. In some cases the process of reducing carbon emissions is already underway, and in others the rules are likely to spur new innovation. Either way the impact on coal use is likely to be “modest.”

Of course, such nuance will not make it into the political response to the new rules, whether it comes to Republicans attacking on them as job crushing government by fiat or to Democrats in coal areas running away from them as fast as possible.

* COMICAL GOP DISSEMBLING ABOUT EPA RULES: Great catch by Glenn Kessler here: Republicans were so quick to criticize the new EPA rules as a dire threat to the economy that they cited a previously completed study based on overly large assumptions about their target emissions targets. It’s almost as if the facts don’t matter to them!

* REPUBLICANS RETOOLING ANTI-OBAMACARE MESSAGE: David Drucker reports that Republicans are increasingly concerned that “repeal and replace” is no longer an effective message, and are planning a revamp:

The term “repeal” has become identified negatively as a partisan Republican talking point that leaves voters with the impression that the GOP wants to move the country from one disliked health care system (Obamacare) to another disliked system (pre-Obamacare). As far as a broad cross-section of Americans are concerned, their country’s health care system is still in dire need of reform. That is why Republicans in the months leading up to the 2014 elections, and beyond, are likely to message their opposition to Obamacare in positive, reform-minded language like “starting over.”

So they’re going to say “start over” instead of “repeal”? Nice. But the real problem with the GOP “repeal and replace” message is that Republicans are unable to offer any alternative solutions, and voters know it.

* AND ROVE GROUP ENTERS ARKANSAS SENATE RACE: National Journal reports that the Rove-founded Crossroads is dumping half a million dollars into a new ad that attempts to tie Dem Senator Mark Pryor to Obama as follows:

In the spot, a grade-schooler is asked to spell “Pryor” in a kind of mock spelling bee. The child responds by spelling out “O-B-A-M-A,” and the judges rule that she was “close enough.”

Hmm, that’ll work. Crossroads also released an internal poll supposedly showing Tom Cotton up by five points, which looks like an effort to shift a storyline about the race that has gotten away from Republicans. The HuffPollster polling average shows Pryor with a two-point lead.

What else?

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