The polls are averages and are obscure b/c many polls come during the tenuous Republican primaries. For instance, a Santorum Ohio or Penn Republican who might not have been for Romney at the time would be for him now.
Obama won't win Nevada by any margin let alone 6.7. He'll more likely lose it by 6.7 (if the SEIU doesn't rig it).
Democrats won Nevada in three of the last five elections. And Harry Reid won despite the GOP throwing everything they had at him.
Again, you work on the assumption that the next six months are going to be kind to Romney. The thing about romney is the more people get to know him, the less they like him.
He was running ahead of Ted Kennedy in 1994- until people got to know him. Ted Beat him by 17 points.
He was running way ahead of Shannon O'Brien in 2002. Until people got to know him. He only won because the Greens and Dems split the vote.
In 2006, the folks in MA knew him too well.. they voted him out.
In 2008, he was running well, until people got to know him. Then he lost to McCain.
In 2012, he ran behind Perry, Cain, Gingrich and Santorum at various times. It's a sad commenttary when your own party has to be dragged kicking and screaming to support you.
We are going to learn a lot more about Romney in the next six months. How whacky thngs Mormons actually believe are, how many working folks he slimed stuffing money in his Cayman Island Bank accounts. Eventually, he's going to have to release the rest of his tax returns and his financials. That ain't going to be pretty.