In a state where three of the last eight governors have gone to prison, the next executive of Illinois will face enormous pressure not only to keep his nose clean but overhaul the state's wild-West reputation.
Quinn, who is poised to succeed Blagojevich should he resign or be impeached, has forged over decades the persona of a populist and a reformer.
He has served alongside Blagojevich since 2003. But Quinn has broken with the governor on several policy issues, and those who know him say he could offer a refreshing change from the breed of politician that has come to characterize officeholders in the Land of Lincoln.
"I think he's very unusual in one way -- he is absolutely honest," said Illinois state Rep. Mike Boland, a Quinn ally in the General Assembly.
Blagojevich is, through his attorney Ed Genson, fighting the House panel reviewing grounds for impeachment. Genson disputed the authority of the committee Wednesday, as the state Supreme Court declined to hear the state attorney general's separate challenge to Blagojevich's fitness to hold office.
Boland said Quinn is just the man to step into the governor's post should it be vacated, since he would press for the kind of campaign finance reform that has eluded the state. Such reforms might have prevented the kind of schemes that Blagojevich allegedly cooked up.
"This is a golden opportunity for reform," Boland said. "Getting reform in Illinois, it's worse than pulling teeth."
He noted that Quinn held a Chicago fundraiser earlier in the week as scheduled, but due to the attention on the state's "pay-to-play" politics the lieutenant governor refused to accept contributions -- even when hundreds of people showed up to honor the official many expect to be the next governor. "That's, like, unheard of here in Illinois," Boland said.
Quinn was involved in public policy long before he became state treasurer in 1991.
One of his most notable achievements came in 1980 when he led a campaign, ultimately successful, to pass an amendment reducing the size of the Illinois House of Representatives by one-third.
"For that he is most loved and hated," said Cynthia Canary, director of the Illinois Campaign for Political Reform.
She called Quinn a "self-styled populist" who even in public office has "continued to beat his own drum."
"Even as lieutenant governor, I think Pat is seen very much as the inside-outer, or the outside-insider," Canary said. "He is in the statehouse, he is in government, but you don't see Pat on the Senate floor or in the governor's office."
Canary cautioned that if he assumes the governorship he'll have to tone down his "gadfly" ways, so as to settle the tensions inflamed by Blagojevich.
"(Blagojevich) was a bully. ... Pat's gonna have to show us a different kind of leadership," she said. "There is a sense of outrage among people that far transcends anything I've ever seen."
Quinn claims he hasn't spoken with Blagojevich since mid-2007, and his stances over the years reflect some friction in the executive branch.
Last year, for instance, Quinn came out in favor of legislation -- pushed by Canary's group -- that would stop state contractors from giving contributions to those officeholders who oversee their contracts. Blagojevich vetoed that bill, and the legislature overrode him.
Quinn and Blagojevich did not run as a pair in 2002. In Illinois, the governor and lieutenant governor candidates run separately in the primaries.
As lieutenant governor, Quinn was known as a steadfast veterans' advocate who attended the funerals of virtually every fallen soldier in his state.
He frequently held Sunday press conferences, staying in the public eye.
House Republican Leader Tom Cross said Quinn's role was largely "ceremonial" as lieutenant governor. But he praised Quinn as an independent mind and fondly recalled working with the lieutenant governor recently on legislation to improve dam safety.
"He'll have to step up and I hope he can, because it's needed for the state," Cross said, adding that he believes Quinn could serve to eradicate the "raw personality conflict" that exists between the sitting governor and the legislature.
Quinn has called on Blagojevich to step down but also fielded criticism from the Illinois Republican Party after he said he might just prefer to make an appointment to fill Barack Obama's vacant Senate seat, rather than wait for a special election. Blagojevich is accused of scheming to sell off that seat.
"The people of Illinois deserve better than another political power grab," the state GOP said in an ad.
Dick Simpson, head of the political science department at the University of Illinois at Chicago, said Quinn would face a state in "desperate" financial shape if he assumes the governorship. He said the scandal surrounding Blagojevich has only made things worse and hurt Illinois' bond rating.
But he, too, hopes Quinn will improve the image of the state.
"I think he'll be a real difference in Illinois from what we're used to," Simpson said. "He won't take bribes, he'll be a straight arrow ... whether he'll have the best public policy we'll have to wait and see."