Vice President Joe Biden. AP Photo/Brennan Linsley A new series of Quinnipiac University polls released Thursday provided more troubling news for former Secretary of State Hillary Clinton — and suggested an opening for Vice President Joe Biden, should he decide to enter the presidential fray.

Biden is running about equal or better with Clinton in head-to-head matchups with potential Republican challengers in the key swing states of Florida, Ohio, and Pennsylvania. And his underlying numbers could put him in better position than Clinton heading into the general election.

Should Biden enter the race, his supporters will likely point to numbers like these to argue that the party would be better served with Biden as its nominee.

Clinton and real-estate magnate Donald Trump lead their respective primaries in the three swing states. But they're also the candidates with the worst favorability ratings, and the ones who are viewed as the least honest and trustworthy.

"Biden, who is spending his time in seclusion, contemplating whether to take on Secretary Hillary Clinton in the Democratic primaries for president, has some new information to consider," said Peter Brown, assistant director of the Quinnipiac University Poll.

"In head-to-head matchups against the three leading contenders for the Republican nomination, he runs as well or slightly better than she does."

Here's a breakdown of Florida:

Clinton still leads the Democratic primary, grabbing the vote of 48% of Florida Democrats. Sen. Bernie Sanders (I-Vermont) gets 15%, while Biden gets 11% as he floats a bid.

Trump leads the Republican primary at 21%, trailed by former Florida Gov. Jeb Bush (R) at 17% and Sen. Marco Rubio (R-Florida) at 11%.

Bush leads Clinton by 11 points in the state. He leads Biden by 13 points.

Sen. Marco Rubio (R-Florida) leads Clinton by 12 points. He leads Biden by six points.

Trump leads Clinton by two points, while trailing Biden by three points.

Clinton has a negative 37% to 55% favorability rating, and voters say by a 64-32 margin that she is not honest and trustworthy. Biden is viewed favorable by a 44-43 margin, and voters say by a 52-40 margin that he is honest and trustworthy.

Republican presidential candidate Jeb Bush at a town hall meeting in North Las Vegas, Nevada Thomson Reuters

A look at Ohio:

Bush trails Clinton by two points in the all-important state, compared with a three-point deficit for Biden.

Rubio leads Clinton by two points, while trailing Biden by one.

Clinton bests Trump in the state by five points, compared with Biden's 10-point lead.

Clinton is viewed unfavorably by a 36-54 margin, and 60% say she is not honest and trustworthy. Biden's favorability is split at 39-43, but 59% of voters say he is honest and trustworthy.

A wild card is Ohio Gov. John Kasich (R), who leads the Republican primary in his home state. But Brown suggested he'll have to broaden his appeal, as he is virtually unknown in Florida and Pennsylvania.

Meanwhile, in Pennsylvania:

Bush leads Clinton by three points, compared with a one-point lead on Biden.

Rubio leads Clinton by seven points, while he leads Biden by three.

Clinton beats Trump by five points in the state, compared with an eight-point lead for Biden.

Just 38% of voters view Clinton favorably in the state, compared with 46% for Biden; 63% say she is not honest and trustworthy. Biden, on the other hand, is viewed as honest and trustworthy by 61% of Pennsylvania voters.

Vice President Joe Biden with then-Secretary of State Hillary Clinton in 2011. REUTERS/Yuri Gripas

"Who gets the love? The one guy who hasn't declared," Brown said. "Vice President Joseph Biden, a Scranton boy made good, is perhaps becoming a more important player in the 2016 presidential race, with a solid grip on the 'from the gut' support of Pennsylvanians."

Though Trump also leads the horse race in all three states, his favorability and "honest and trustworthy" scores linger far behind. In the three states, he's viewed favorably by no more than 34% of voters. And a majority in all three states considers him not honest and trustworthy.

As Brown noted, no presidential candidate since 1960 has won a general election without winning at least two of these three states. Pennsylvania is increasingly coming into play as a swing state to watch in 2016, as the Cook Political Report last week moved the state from one that "leans" Democratic to a "toss-up."

Controversy over Clinton's use of a private email server at the State Department continues to cast a shadow over her presidential campaign, providing a potential opening for Biden. Greg Valliere, the chief political strategist at the Potomac Research Group, called the results "stunning."

"She has a new problem today — Quinnipiac polls just released ... that show Joe Biden running as well if not better than Hillary in matchups with Republicans in key states," he said. "This is stunning — she's in real trouble."

The Republican rapid-response group America Rising was quick to chart Clinton's declining numbers in the three swing states: