"You never want to say no to the president of the United States," Edgar told a news conference, but he refused to reconsider.
The popular two-term Republican has been a lecturer on the political science faculty at the University of Illinois at Urbana-Champaign since leaving office four years ago. Sources said Edgar's wife, Brenda, was relieved when he announced he was retiring from active politics and opposed him returning to the rough and tumble of a grueling Senate campaign that would require non-stop fundraising.
"After a lot of consideration we've decided not to run as a candidate for the United States Senate next year," Edgar said.
He said Brenda never asked him not to run.
"It's an early Mothers Day gift. It is a gift to her. It's something we talked about," he said. "It's a family decision. Both of the children who are no longer in Illinois have strong feelings about it as well."
Edgar, 56, had quadruple bypass surgery in 1994 and underwent two angioplasties to clear blocked arteries near his heart while in office.
He said his health is fine and did not rule out a future political comeback. Edgar reportedly has enjoyed being out of politics and has increased his income substantially in the private sector since leaving office in January 1999.
Edgar said held statewide office for nearly 20 years and in state government for nearly three decades. Edgar said he believes he could have won a Senate race.
"I have never looked at going into a statewide campaign with better numbers and more support," he said.
He said he told White House political adviser Karl Rove of his decision in a phone call Friday morning before the hastily called news conference.
"He expressed disappointment, but understood," Edgar said.
Illinois is seen as a battleground state for Republicans to maintain control of the Senate in 2004.
"It really takes an awful lot to do it (run for Senate). It just wasn't worth it," said Michael Sneed, gossip columnist for the Chicago Sun-Times. "The president courted him and everybody else courted him. He decided no, it just wasn't worth it."
Sneed said Edgar chafed at the thought of anyone questioning his ethics after the drivers-licenses-for-bribes scandal that plagued former Gov. George Ryan throughout his term. Ryan did not run for a second term and Illinois voters elected Rod Blagojevich, a Chicago congressman, the state's first Democratic governor in 26 years.
Illinois state Treasurer Judy Baar Topinka, the only Republican currently holding statewide office, immediately became the favorite in a GOP primary but Topinka has said as state party chair, she is more interested in keeping the party alive.
Other possible candidates include former attorney general Jim Ryan, who lost to Blagojevich last year, former investment banker Jack Ryan, who left the business world three years ago to teach school, former Lt. Gov. Corinne Wood and former state Sen. Patrick O'Malley.