Beat me by a few seconds ... 
The D+10 sample applies to all adults though, which means the RV sample is probably D+7 or so - similar to 2008. Makes sense, because Obama voters in this poll say they are more motivated than Romney voters. And there are much more registered Democrats in the country anyway than Republicans.
I'll be surprised if in November, Democratic turnout is D+7, enthusiasm polling aside. There's no way he will catch that same level of excitement again, not after 4 yrs of this economy. Democratic turnout advantage has not been that high since 1980. Also, registration aside, Rasmussen seems to think that Partisan Identification, nationwide, favors Republicans. http://www.rasmussenreports.com/public_content/politics/mood_of_america/partisan_trends. And before anyone attacks Rasmussen, consider that their reported nationwide partisan trends in Oct. 2008 were 40% Dem and 33% Rep. The actual turnout that November was nearly identical (39%Dem, 32%Rep).
Either way, good news for Mitt that he's polling at 49-45%/49-46% with a D+10 sample.
Al Gore, John Kerry, and Barack Obama have done badly in holding onto southern working-class white Democrats that Carter could rely upon in 1976 and that Clinton could rely upon in 1992 and 1996. Democrats have recently won the Governorship of Kentucky and Senate seats in West Virginia with such voters. In a State that has a huge Southern component in its electorate, an incumbent Senator is doing far better than the President.
President Obama has been poaching people who fit the old demographic of "Rockefeller Republicans" heavily concentrated in the North and West away from the Republican Party to an extent that no Democrat has done since LBJ in 1964. Such explains how Barack Obama can keep States like California and New York, as well as New England, out of contention. They may be pro-business enough to vote for Ronald Reagan, but Republicans who push the envelope with the anti-rational, anti-feminist, and repressive agenda of the Hard Right have deep trouble in parts of the country in which such is alien.
People who could vote for Ed Brooke, John or Lincoln Chaffee, Tom McCall, Bob Packwood, Gordon Smith, or Charles Percy can vote for Barack Obama. He is ideologically similar to them.
One might have ignored this phenomenon, but Republicans ignore this at the peril of defeat. Such states as Ohio, Virginia, Florida, and Colorado have many such people. Indiana and North Carolina have more of them than might seem obvious. Except for Texas and the heavily-Mormon and Lutheran parts of America, President Obama has for all practical purposes resuscitated the "I Like Ike" coalition so effectively that had he won only the one state that he won and Eisenhower ever lost he would have endured one of the worst landslides in the electoral vote to have ever occurred. (I am going to guess that Ike would have won Hawaii and -- surprise! -- the District of Columbia. The black majority in DC would have never voted for a Democrat who appealed heavily to Southern white people hostile to blacks).
