However, Edgar lost some of that aura Monday when he endorsed an old friend's 2010 campaign for governor.
"Today, I'm endorsing Kirk Dillard for governor of Illinois," he said.
Senator Dillard hinted for several weeks the endorsement was eminent. Former two-term governor Edgar, for whom Dillard worked as chief of staff in the early 1990s, will support the Naperville senator's campaign to be the next Illinois governor.
"Illinois now faces probably the greatest financial mess it's ever faced, and it's going to take someone with the experience and willingness to provide the leadership to get the state back on track," Edgar said.
"Even though he's been out of office for 10 years, Jim Edgar is still the most respected figure in the Land of Lincoln," Dillard said.
Dillard's four announced primary opponents were not so impressed.
"This is not about politicians endorsing other politicians," businessman Dan Proft said.
DuPage County Chairman Bob Schillerstrom said, "The Republican Party and Illinois must break from the past with fresh voices and new solutions."
"My campaign is about tomorrow, not yesterday," said Bloomington State Sen. Bill Brady.
"I guess, the only question is, did things work yesterday. And if they did, maybe they'd work tomorrow. Because what they're doing today is sure not working," said Edgar.
Republican candidate Adam Andrzejewski remembered how, 17 years ago, Edgar worked against the rollback of a temporary tax increase. And the conservative businessman said the party's powerful right wing will never forgive Dillard for his kind words in 2008 about Barack Obama's ethics.
"The fact that Kirk Dillard cut the commercial of endorsement in the Iowa primary for Barack Obama, that hurts Kirk Dillard in this Republican primary," Andrzejewski said.
"It was clear to Senator Obama at the time that I fully supported John McCain for president, and it wasn't an endorsement. It was about ethics. That's what that ad was about," said Dillard.
Senator Dillard also said he hoped the Edgar endorsement would separate him from the other candidates in the race. His opponents say Dillard is a separate item now, the candidate of the past.
There is another major candidate lurking in Republican primary for governor. Former party chairman Andy Mckenna, reportedly, will run, but he has not made a formal announcement.