On the day that Sen. Marco Rubio announced he plans to seek reelection, the Florida Republican leads the two Democratic candidates in the state's Senate race.
A Quinnipiac University poll released Wednesday found Rubio leads Rep. Patrick Murphy 47 percent to 40 percent and Rubio also leads Rep. Alan Grayson 48 percent to 40 percent. Murphy and Grayson, however, lead other GOP contenders who are largely unknown, the poll said.
In Pennsylvania, Republican Sen. Pat Toomey leads Democratic challenger Katie McGinty 49 percent to 40 percent in the Senate race.
In Ohio, Republican Sen. Rob Portman ties former Gov. Ted Strickland 42 percent to 42 percent in that state's Senate race.
Rubio's decision to seek reelection came in the wake of the the Orlando shooting on June 12. He dropped out of the presidential race in mid-March and said at the time that he would retire from Congress at the end of the year.
The poll focused on the those three key swing states because no candidate has won the presidential race since 1960 without winning at least two out of three of the states.
The poll found 45 percent of Florida voters approve of Rubio's job in the Senate compared to 44 percent who disapprove. Forty-four percent of Ohio voters approve of Portman compared to 32 percent who gave him a negative rating and nearly half of Pennsylvania voters approve of Toomey's job performance compared to 38 percent who disapprove.
A Quinnipiac University poll released Tuesday found that Hillary Clinton is leading Donald Trump in Florida by 8 percentage points, but they're virtually tied in Pennsylvania and in a dead heat in Ohio.
The Senate poll surveyed between 950 and 975 voters in each state between June 8 and 19 with a roughly 3 percentage point margin of error.