The latest NYT-CBS News-Quinnipiac University poll confirms the greatest hopes -- and fears -- of the GOP.
Mitt Romney's choice of Paul Ryan as his running mate did put Wisconsin in play, but the Medicare issue remains a big liability in key battleground states.
In the Badger State, the matchup between President Obama and Romney has tightened up – from an Obama lead of 6 points in a similar poll on Aug. 8 to just two points into the survey released today. Obama leads Romney, 49 percent to 47 percent in Wisconsin a little less than two weeks since the presumptive Republican nominee put Ryan on the ticket.
In Florida too Romney is making some inroads, now trailing Obama by just 3 percentage points -- 46 percent to 49 percent.
But while the margin in Wisconsin is narrowing, Ohio is now drifting from "toss-up" to "lean Obama" -- proof that the heavy air assault on Romney this summer has been brutally effective. The poll shows Obama at 50 percent in Ohio compared to Romney's 44 percent.
Winning Wisconsin, but losing Ohio would mean that to win the Electoral College, Romney would still need to run the table and carry Virginia, North Carolina, Iowa, New Hampshire, and Nevada (or Colorado). (Remember, Ohio has 18 electoral votes; Wisconsin has just 10.)
Meanwhile, Obama can surpass the magic number by winning just three of those states -- Colorado, Nevada and Virginia.
In fact, looking at the battleground states, map, Romney would have to pick up Florida, North Carolina, Virginia, Wisconsin, Iowa, Nevada and Indiana just to get to a 269-269 Electoral College tie.
One senior Republican told ABC News he thought Romney's team was beginning to wonder if Ohio is a bridge too far -- which was partly why Ryan was picked, as part of an alternative strategy involving Wisconsin and other states.
However, that's not to say that the campaign has given up on Ohio. Both Romney and Ryan will be campaigning together in the state on Saturday.
With additional analysis from ABC News' George Stephanopoulos and Jake Tapper