(CBS News) The struggling economy is without question the best issue for Mitt Romney on the presidential campaign trail, but a new poll shows that voters in three key swing states are split over whether he or President Obama would be a better economic steward.
Additionally, the new Quinnipiac poll shows that voters in Ohio, Pennsylvania and Florida approve of Mr. Obama's new immigration policy and believe the president would be better than Romney at handling the issue of immigration. Voters in Florida -- where the Latino vote could play a key role -- approve of Mr. Obama's new policy by the widest margin.
The president holds leads over Romney in all three states -- he leads by four points in Florida, nine points in Ohio and six points in Pennsylvania -- but this far from Election Day, those numbers could easily change.
Peter Brown, assistant director of the Quinnipiac University Polling Institute, noted in the poll's release that for much of the last year, more swing state voters thought Romney would do a better job handling the economy, but that advantage has disappeared for now.
In Ohio -- a must-win state for Romney -- voters say 47 percent to 42 percent that Mr. Obama would be better than Romney at handling the economy. Similarly, they say Mr. Obama would be better for their personal economic future, 47 percent to 42 percent.
In Florida, voters say Romney would do a better job than Mr. Obama at handling the economy, 46 percent to 44 percent -- within the poll's 2.8 percent margin of error. Forty-six percent say Mr. Obama would be better for their personal economic future while 45 percent say Romney would.
Pennsylvania voters are split at 44 percent to 44 percent over which candidate would do a better job handling the economy. Forty-four percent say Mr. Obama would be better for their personal economic future, compared to 43 percent who say Romney.
CBS News political director John Dickerson notes that Mr. Obama is doing especially well in Ohio -- where the president has hit Romney the hardest on his record as the head of the private equity firm Bain Capital. The line of attack appears to have had an effect particularly among independents in Ohio. In May, Romney was leading 43 percent to 38 percent among independents in a Quinnipiac poll, but now Mr. Obama leads 45 percent to 36 percent.
The issue of immigration, meanwhile, is far less pressing to voters, but it could have a notable impact among key constituencies like Florida Hispanics.
Florida Hispanics support Mr. Obama 56 percent to 32 percent, the latest survey shows. By comparison, they backed him 49 percent to 39 percent in a Quinnipiac poll released June 21 - which was after Mr. Obama announced he will stop deporting certain undocumented youth, but before both candidates made major speeches to a Hispanic organization at an Orlando conference.
Voters in Florida support Mr. Obama's immigration initiative 58 percent to 33 percent. Ohio voters back it 52 percent to 38 percent, and Pennsylvania voters support it 51 percent to 41 percent.