And yet another Democrat said he would likely seek Corbett's job in 2014.
All this as the governor prepares to enter what could be the critical period in his tenure. Next week, he delivers his annual budget speech to the legislature, during which he will also introduce a plan to rein in skyrocketing public pension costs as well as find the billions needed for roads, bridges, and mass transit. And on Wednesday in Pittsburgh, Corbett is scheduled to finally detail his proposal for privatizing Pennsylvania's oft-maligned state liquor stores.
Each initiative will require nimble negotiating with the Republican-controlled legislature, and will be widely viewed as a test of Corbett's political and governing skills as he gets closer to asking voters for a second term.
For his part, the governor was not letting Tuesday's news get him down. Spokesman Kevin Harley said Corbett spent part of the day outside Pittsburgh delivering good news about how his budget would fund three new classes of cadets for the state police.
"He's been having a great day," Harley said.
Harley said it was normal for poll numbers to fluctuate, and noted that the governor has nearly two years left in his first term.
"He has a lot of governing to do between now and then," Harley said. "The first two years were about getting the state's fiscal house in order. And he did that. Now, the governor has an ambitious spring agenda which he believes will continue to help the state grow and prosper."
But there was dissension in his party's ranks. In a wide-ranging interview with reporters Tuesday, Senate President Pro Tempore Joe Scarnati (R., Jefferson) signaled that he was unhappy with the way the administration had handled the politics behind some of its policy initiatives.
Corbett, for instance, has said a priority this year is finding a way to stanch the growing cost of pensions for state employees and public school teachers. He and others in his administration warned recently that if the legislature did not work with them, they would find other places to cut - with public education a likely target.
Scarnati said that smacked of "Washington-style politics," adding, "I'm not going to play that game."
"The issue of cutting public education is a very sensitive issue," he said, "for myself, for members of our [Senate GOP] caucus and members of the General Assembly. And putting an either-or does not make this budget a lot easier to get done."
He also acknowledged that relations between his caucus and the administration could stand improvement.
"We like to work with everybody - and working with everybody is a two-way street," Scarnati said, adding that he had often learned of the administration's initiatives or positions through the media rather than directly from the governor. "The key here is, we have a lot of tough things to do . . . and we need to work together."
The Quinnipiac survey contained additional bad news from Republican voters. Just 49 percent said they would support Corbett if the election were today. And 51 percent of all voters said Corbett did not deserve reelection, to 31 percent saying he did.
Overall, 42 percent disapproved of the job Corbett is doing, to 36 percent who approved.
The anemic poll showing means Corbett is pushing an ambitious legislative agenda while his popularity is at low ebb, potentially limiting his leverage.
But poor polling 21 months out does not necessarily predict his political demise.
Since 1968, when the state began letting governors seek second terms, five have done so and all have won. All but one had weak poll numbers heading into that second campaign, including Ed Rendell, Corbett's predecessor. Yet Rendell won a second term easily.
Political strategists also know that midterm elections such as next year's draw fewer voters than presidential races, so the electorate is likely to be smaller and more Republican-leaning that in 2012. In addition, the party that holds the White House usually loses ground in off years.
A persistent problem for Corbett is a gender gap. In the new poll, women disapproved of his performance by 45 percent to 31 percent; men narrowly gave him a thumbs-up, 41-37.
Overall, voters disapproved of his handling of the Jerry Sandusky child sex-abuse scandal at Pennsylvania State University by nearly 2-1, though they supported his recent decision to sue the NCAA for its sanctions against the school.
Pollsters surveyed 1,221 registered voters between Jan. 22 and Sunday, with the results subject to a statistical margin of error of plus or minus 2.8 percentage points.
Tim Malloy, assistant director of Quinnipiac's polling institute in Connecticut, likened Corbett's political situation to football. "If he were running a football team instead of a state, he'd fire his offensive coordinator," Malloy said. He said Corbett had reached a 50 percent approval rating only once, in September 2011, "mainly because of his bad grades from women."
Corbett's ratings help explain the growing field of Democrats pondering a run against him. One Republican, Montgomery County Commissioner Bruce L. Castor Jr. has said he, too, is considering a primary challenge. On the Democratic side, John Hanger, a former state environmental secretary, has declared his candidacy. On Tuesday, Tom Wolf, a York businessman who served as Rendell's revenue secretary, said he was close to announcing he would run.
"I really want to do this," Wolf said in an interview.
Contact Angela Couloumbis at 717-787-5934 or firstname.lastname@example.org, or follow on Twitter @AngelasInk.
Inquirer staff writer Amy Worden contributed to this article.