A new Quinnipiac University swing state poll released Thursday shows Republicans are leading the way in all but one potential matchup against Democrats in Florida.

Former Secretary of State Hillary Clinton and Donald Trump are clear winners in the Democratic and Republic primaries in Florida, Ohio and Pennsylvania, but Vice President Joe Biden runs as well as or better than Clinton against top Republicans in general election matchups in these three key swing states, according to the poll.

Republicans would win all general elections matchups in Florida except if Biden were to face Trump (Biden has 45 percent compared to Trump's 42 percent).

While they lead the race for the nominations, Clinton and Trump have the worst overall favorability ratings among all voters of any of the leading candidates and the lowest scores for being honest and trustworthy, the poll found.

The swing state poll focuses on Florida, Ohio and Pennsylvania because no candidate since 1960 has won the presidential race without taking at least two of the three states.

Former Florida Gov. Jeb Bush and Sen. Marco Rubio, of Florida, both run better than Trump against Clinton, Biden or Sen. Bernie Sanders, of Vermont.

In Florida, Clinton has 48 percent of Florida Democrats, followed by 15 percent for Sanders and 11 percent for Biden, with 17 percent undecided.

Among Republicans, Trump gets 21 percent, with 17 percent for Bush and 11 percent each for Rubio and Ben Carson. No other candidate tops 7 percent, with 8 percent undecided.

General Election scenarios (Florida voters only):

  • Jeb Bush (R) 49%, Hillary Clinton (D) 38%
  • Marco Rubio (R) 51%, Hillary Clinton (D) 39%
  • Donald Trump (R) 43%, Hillary Clinton (D) 41%
  • Jeb Bush (R) 51%, Joe Biden (D) 38%
  • Marco Rubio (R) 48%, Joe Biden (D) 42%
  • Joe Biden (D) 45%, Donald Trump (R) 42%
  • Jeb Bush (R) 54%, Bernie Sanders (D) 35%
  • Marco Rubio (R) 52%, Bernie Sanders (D) 36%
  • Donald Trump (R) 45%, Bernie Sanders (D) 41%
  • Hillary Clinton (D) 37%, Jeb Bush (R) 36%, Donald Trump (NPA) 19%

From Aug. 7 to Aug. 18, Quinnipiac University surveyed:

  • 1,093 Florida voters with a margin of error of +/- 3 percent. The survey includes 477 Republicans with a margin of error of +/- 4.5 percent and 345 Democrats with a margin of error of +/- 5.3 percent.
  • 1,096 Ohio voters with a margin of error of +/- 3 percent. The survey includes 371 Republicans with a margin of error of +/- 5.1 percent and 353 Democrats with a margin of error of +/- 5.2 percent.
  • 1,085 Pennsylvania voters with a margin of error of +/- 3 percent. The survey includes 443 Republicans with a margin of error of +/- 4.7 percent and 462 Democrats with a margin of error of +/- 4.6 percent.

Live interviewers called land lines and cellphones.

Open in a new tab: Quinnipiac University's swing state poll, Aug. 20, 2015 (PDF)

Read the Quinnipiac University swing state poll (Aug. 20, 2015)