Public Policy Polling's latest survey shows Democrat Richard Carmona has taken a lead over Republican Jeff Flake.

The Democrat-leaning polling firm notes that Carmona is winning the independent vote and grabbing some GOP crossover. But the pollsters also note that "this race could shift back in Flake's favor."

This is the first attributed poll to show Carmona with a lead over Flake. As we note in this week's Skinny, which will be online later today and is now hitting streets in our print edition, three different firms polls from last week showed a tightening race: One was from the GOP-leaning Rasmussen Reports, which showed Flake with an 6-point lead (Flake 47%; Carmona 41%); one was from Carmona’s campaign, which showed Flake with a 1-point lead (Flake 44%-Carmona 43%); and one was from Moore Information, which showed Flake with a 3-point lead (Flake 43%-Carmona 40%).

Here's the release from Public Policy Polling:

PPP's newest poll of the Arizona Senate race finds Democrat Richard Carmona leading Republican foe Jeff Flake 45-43. That represents a small shift in Carmona's direction since our last poll of the state three weeks ago, which had found Flake ahead by just a 44-43 margin.

There's two things you have to do to win as a Democrat in a pretty Republican leaning state like Arizona: win independents and a get a healthy amount of crossover support from GOP voters. Right now Carmona's doing both of those things. He has a 52/37 advantage over Flake with independents. And he's winning over 14% of Republicans while losing just 7% of Democrats. Carmona's net favorability is a +8 spread (35/27), while Flake's is -1 at 40/41.

There are still reasons to think this race could shift back in Flake's favor. The 12% of voters who are undecided prefer Mitt Romney over Barack Obama for President by a 58/37 margin, so there's reason to think they might end up breaking toward Flake in the end. Also Arizona voters would generally prefer that Republicans be in control of the Senate rather than the Democrats by a 50/40 spread. That Carmona leads anyway is a function of him being superior to Flake as a candidate, but that still leaves open the possibility that if Republicans can effectively nationalize the election Flake's standing will improve.

One thing there's zero doubt about: who would have thought two months ago Democratic prospects in the Arizona Senate race would be better than Republican ones in the Missouri contest?

Arizona may go Democratic in the Presidential race sometime but it doesn't appear likely to be this year. We find Mitt Romney leading Barack Obama 53-44 in the state. This is a rare state where a majority of voters actually see Romney favorably. 54% have a positive opinion of him to 42% with a negative one. And Obama's quite unpopular with just 40% of voters approving of him to 57% who disapprove.
Other notes from Arizona:

-Voters are closely divided on Jan Brewer with 47% approving of her to 46% who disapprove. They're leaning toward keeping the Governor's office in GOP hands in 2014 at this early stage- 48% say they'd generally speaking like the next Governor to be a Republican to 40% who prefer a Democrat.

-John McCain's approval numbers in his home state are the best we've found for him since his Presidential campaign. 51% of voters approve of the job he's doing to 39% who disapprove. A higher than normal 67% of Republicans are giving him good marks, and he has healthy crossover support with 32% of Democrats approving of him as well.

-As he heads for the door Jon Kyl has a 44% approval rating with 36% of voters disapproving of him.