Now, he told the Chicago Sun-Times, he is coming home for good at the end of the year to run for president of the Cook County Board in 2010.

Not as a Democrat, which he has been all his life, but as a Republican.

For the kinetic Vallas who thrives on challenge, it will be that and more.

The last Republican to win that office was Richard Ogilvie in 1960, and since that time, Cook County has only become more Democratic. Then again, in politics, timing is everything. Just as the implosion of now-imprisoned Gov. George Ryan opened the door to the Democrats after 26 years of Republican rule, the scandal surrounding Rod Blagojevich and the economic crisis that consumes government in Cook County present a rare shot for this state's beleaguered GOP. And party leadership seems ready to take it, unbothered by Vallas' lack of Republican credentials.

"I think he'd be an excellent candidate," House Republican leader Tom Cross said by phone Tuesday. "He'd be great for Republicans, great for Cook County, [with] impeccable credentials, substance and integrity."

Vallas spent the last two days meeting with Cross and other Republican officials, including state chairman Andy McKenna and Cook County chairman Lee Roupas.

Though Vallas said he is forming an exploratory committee to assess how much support and money are out there, as this column first reported back in August, he has been putting this plan together for many months. That's why he turned down an invitation to address the Democratic National Convention last summer, unwilling to give allies of the current president of the Cook County Board, Todd Stroger, any opportunity to box him as a Democrat as he was preparing to jump political ships.

Vallas fell out of favor with the mayor in 2001. Though he raised test scores, opened new schools and instituted a wide variety of reforms as CEO of Chicago schools, he had also achieved an outsized profile for a subordinate.

He has been a lightning rod for praise and criticism.

Dale Mezzacappa, a Philadelphia education reporter, wrote in 2008, "Vallas lasted longer in both Chicago and Philadelphia than most school leaders . . . but wore out his welcome in both places. He left the Philadelphia district in many ways transformed, most agree for the better, but still with a sour taste and a big deficit."

Vallas now works for Republican Louisiana Gov. Bobby Jindal rebuilding New Orleans schools from the ground up in the wake of Hurricane Katrina, getting largely good reviews. Vallas says his work will be finished by the end of this year with a transition team ready to move into place.

Though two years ago Vallas considered running again for governor against Blagojevich, his residency was raised as an issue. His allies say fellow Democrats were behind court efforts to stop him. As Vallas wryly points out, "Nobody tried that with Alan Keyes," a Republican who ran for Senate in 2004.

Vallas' family moved to Palos Heights two years ago. He commutes to and from New Orleans. Residency is no longer a problem.

Money will be an issue. Vallas, with the help of his brother Dean, personally paid off a $537,000 campaign debt from 2002.

"We've promised our wives that won't happen again," Dean Vallas said Tuesday.

Never afraid of provoking controversy, Vallas is willing to declare Cook County "broken" but less willing to say who broke it. Is he, for instance, implicitly pointing the finger at Todd Stroger? Or his father who held that office before him? "I'm not taking shots at anybody," he said. "I'll run on my own resume."

Will it matter that that resume, until now, never included anything about being a Republican?

"People aren't looking for someone ideologically or politically correct," he declared. "They're just looking for competence."