A new poll conducted for American Crossroads, the independent conservative group conceived by GOP leaders including Karl Rove and former Republican National Committee Chairman Ed Gillespie, suggests the 2010 landscape might be just volatile enough to give Republicans at least a chance at that prize.

The survey, which gauged voter sentiment in 13 of the states with the country’s most competitive Senate races, showed Republican Senate candidates averaging a high single-digit lead over their Democratic opponents, offering the same snapshot of an angry, uneasy electorate shown in poll after poll this year.

The Republican firm Public Opinion Strategies conducted the poll, testing 1,300 likely voters across the 13 states, for a small state-by-state sample of 100 respondents. That means that for the individual races, the survey’s margin of error is so wide as to render the results effectively meaningless.

But taken together, the results suggest Republicans have an opening to make substantial gains this fall, even to the point of putting the Democrats’ 59-seat majority in peril. In eight seats currently held by Democrats – Arkansas, Colorado, Delaware, Illinois, Indiana, Nevada, Pennsylvania and Washington – Republican candidates average an edge of seven points over their Democratic opponents, leading 47 percent to 40 percent.

In five Republican-held seats – Florida, Kentucky, Missouri, New Hampshire and Ohio – GOP candidates hold an average lead of eight points, 45 percent to 37 percent.

The survey tested specific candidates – Republican nominees or frontrunners against their Democratic counterparts – in every state except for Colorado, where this week’s primaries remained too close to call. Florida Gov. Charlie Crist was listed as an independent candidate in his state’s Senate race.

Pollster Glen Bolger ran the survey, modeling it on an NPR-sponsored poll that Public Opinion Strategies conducted in June with the Democratic firm Greenberg Quinlan Rosner. That poll found that in the 70 most competitive House districts, voters leaned to Republican candidates by eight points, 49 percent to 41 percent.

Bolger told POLITICO the American Crossroads poll gave a similar snapshot of the Senate campaign, explaining: “Individual races may turn out okay, but the overall wave is as strong against [Democrats] as it is against Democrats in the House.”

“You’ve got independents voting Republican, two to one, just like McDonnell, Brown and Christie had,” Bolger said, referring to the 2009 victories of Virginia Gov. Bob McDonnell and New Jersey Gov. Chris Christie, and the 2010 special election win of Massachusetts Sen. Scott Brown. “You have the high-interest voters much more supportive of Republicans than the overall electorate, even.”

Bolger’s poll asked voters to rate their interest in the election on a scale of one to 10; among those who rated themselves an eight or higher, Republicans led by 26 points, 52 percent to 36 percent. Independents are breaking for the GOP by a similar, 22-point margin, 47 percent to 25 percent, and just 21 percent of them say the country is on the right track.

More Americans still say former President George W. Bush is responsible for the recession than say President Obama is to blame, 52 percent to 33 percent. But that doesn’t seem to affect voters’ responses to the two parties’ midterm messages.

Presented with a generic Republican pitch (“The bailouts failed. The stimulus failed. And the health care bill will cost too much money. … My top priority will be to bring down the deficit and work to create jobs, not kill jobs”) and a generic Democratic message (“They left America with rising bailouts, deficits and unemployment. So, I’m fighting for small business and the middle class, not the big guys. … We can’t go back to policies that hurt the middle class”) voters picked the Republican message by eight points, 52 percent to 44 percent.

Still, the poll doesn’t mean Democrats are likely to lose the Senate – it doesn’t even mean definitively that the Senate is in play. For Republicans to take control of the chamber, they would have to win every seat named in the survey, plus two more from a list of Democratic incumbents topped by Wisconsin Sen. Russ Feingold and California Sen. Barbara Boxer. Republicans would also have to maintain control of Louisiana Sen. David Vitter and North Carolina Sen. Richard Burr’s seats, which Democrats have vowed to target.

Other state-by-state polling has given Democrats more encouragement in several of the key races. Senate Majority Leader Harry Reid, after trailing his possible Republican challengers all cycle, has now posted several small leads over former state Assemblywoman Sharron Angle. Pennsylvania Rep. Joe Sestak has never fallen far behind former Republican Rep. Pat Toomey in the fight for outgoing Sen. Arlen Specter’s seat. Multiple polls have shown Republicans in real danger of losing all five open seats the American Crossroads survey examined.

To American Crossroads, however, the point of the poll is the big picture: the voters who will ultimately decide the fate of the Senate campaign are mad as hell, and seem unlikely to take it anymore.

“There’s a sense that while the Democratic House might be in danger, a Democratic Senate is somehow safe – but the findings here really contradict that conventional wisdom,” American Crossroads spokesman Jonathan Collegio said. “Each of the last seven times the House changed power since 1932, the Senate fell in the same year, and there’s abundant evidence here that history will continue to repeat itself.”

That’s a possibility MSNBC’s Chuck Todd floated in late July. Asked for his prediction for the fall campaign, Todd said he’s inclined to believe “Republicans win them both or they don’t win either. They win both the house and the Senate, this thing goes to 45, 50 seats and 10 in the Senate, or neither one happen.”

The Public Opinion Strategies poll tested 1,300 likely voters in 13 states, from Aug. 2 through Aug. 5. The survey had a margin of error of plus or minus 2.72 percent.

CORRECTION: This story has been updated to include a more precise description of Rove and Gillespie’s involvement in American Crossroads.