(CBS News) Mitt Romney's selection of Paul Ryan as his running mate appears to have energized some likely voters in Ryan's home state of Wisconsin, according to a new Quinnipiac University/CBS News/New York Times poll.
As many as 31 percent of Wisconsin voters say Romney's pick of their native son makes them more likely to support Romney in the fall, according to the survey, conducted Aug. 15-21. Fewer (22 percent) say they would be less likely to do so while 45 percent say Ryan's selection makes no difference.
With Ryan joining Romney's campaign, the Republican presidential candidate has gained ground in Wisconsin, where President Obama now leads by just two points, 49 percent to 47 percent. The two-point lead is within the poll's margin of error.
"It seems like the pick of Paul Ryan has had some small beneficial effect for Mitt Romney," Peter Brown, the assistant director of the Quinnipiac poll, told CBS News' Bill Plante on "Face to Face".
Referring specifically to Wisconsin, Brown added, "Obviously, it's had some home-team effect."
The race has tightened in Florida, where Mr. Obama is leading 49 percent to 46 percent - equal to the poll's three-point margin of error. Romney holds a double-digit lead among seniors in the Sunshine State.
Mr. Obama has maintained his lead in Ohio, according to the poll, besting Romney 50 percent to 44 percent. The president enjoys a 13-point advantage among women and backing from young voters in Ohio, while Romney wins the support of independents and has an 8-point lead among seniors.
Few likely voters are undecided in these battleground states, and nine in 10 say their minds are made up. Only one in 10 says they could change their minds about who to support.
In all three of these battleground states, Republicans are more enthusiastic than Democrats about voting this year. Republican enthusiasm about voting has also risen from earlier this month.