Ohio's Rob Portman is among Republican incumbent senators who have solid leads over Democratic challengers in the key swing states according to a Quinnipiac University Swing State Poll.

Former Ohio Gov. Ted Strickland, who had an early lead but now trails Sen. Rob Portman by 7 percentage points.

The Swing State Poll focuses on Florida, Ohio and Pennsylvania because since 1960 no candidate has won the presidential race without taking at least two of these three states.

The U.S. Senate matchups show:

  • Ohio - Sen. Rob Portman over former Gov. Ted Strickland 47 - 40 percent;
  • Pennsylvania - Sen. Pat Toomey over Democrat Katie McGinty 49 - 39 percent.
  • Florida - Sen. Marco Rubio over U.S. Rep. Patrick Murphy 50 - 37 percent, and Rubio leading U.S.Rep. Alan Grayson, another possible Democratic challenger 50 - 38 percent;

"The numbers seem to be breaking the Republican way in the battle for control of the U.S. Senate, at least when it comes to the critical swing states of Florida, Ohio and Pennsylvania," said Peter A. Brown, assistant director of the Quinnipiac University Poll.

"In Ohio, Sen. Portman had trailed for much of the campaign, but now has moved clearly ahead of Democratic challenger Ted Strickland, a former governor. In Pennsylvania, incumbent Sen. Pat Toomey, who has led from the start, maintains a double-digit margin."

Ohio poll breakdown:

Gender and racial gaps are wider in Ohio as men back Portman 55 - 35 percent, while women back Strickland 46 - 41 percent. White voters go Republican 52 - 37 percent, while non-white voters go Democratic 59 - 23 percent.

Independent voters back Portman 49 - 39 percent.

Ohio voters approve 46 - 35 percent of the job Portman is doing and give him a 40 - 32 percent favorability rating.

Strickland gets a slightly negative 38 - 42 percent favorability rating.

Voters approve 48 - 30 of the job Sen. Sherrod Brown is doing and approve 58 - 32 percent of the job Gov. John Kasich is doing.

"There's a seeming paradox about the U.S. Senate race in Ohio. Democrat Ted Strickland, who will be 75 years old next month, does best among young voters, beating incumbent Republican Sen. Rob Portman 49 - 36 percent among voters 18 to 34 years old. Portman, who is 60 years old, scores best among voters over 65 years old, beating Strickland 51 - 35 percent," Brown said.

Pennsylvania poll breakdown:

The man-woman matchup in the Pennsylvania Senate race produces only a small gender gap. Men back Toomey 53 - 35 percent, while women are divided with 45 percent for Toomey and 42 percent for McGinty.

There is a larger racial gap as white voters go Republican 55 - 35 percent, while non-white voters go Democratic 54 - 23 percent.

Pennsylvania voters approve 47 - 39 percent of the job Toomey is doing and give him a 45 - 34 percent favorability rating.

McGinty gets a split 29 - 29 percent favorability rating and 41 percent don't know enough about her to form an opinion.

Voters approve 44 - 32 percent of the job Robert Casey Jr. is doing and disapprove 50 - 40 percent of the job Gov. Tom Wolf is doing.

"Republicans, at least in Pennsylvania, can exhale. Sen. Pat Toomey has a comfortable lead in his bid to keep this GOP Senate seat safe. A welcome development in the turbulent and polarizing landscape where Donald Trump roams," said Tim Malloy, assistant director of the Quinnipiac University Poll.