WASHINGTON - A defiant Illinois Governor Rod Blagojevich, accused of trying to sell Barack Obama’s Senate seat to the highest bidder, picked a former state attorney general for the post to send the Democratic political machine into a tizzy.

The governor’s surprise appointment of Roland Burris - a lobbyist and Blagojevich campaign donor - Tuesday marked another unexpected turn in the federal corruption case that surfaced with his Dec 9 arrest by FBI agents in Chicago.

Blagojevich, who has the sole authority to name a successor to serve out the last two years of President-elect Obama’s unfinished senate term until 2010, returned to the governor’s mansion within hours on a $4,500 bail with his constitutional prerogative intact.

But opposition was so widespread to Blagojevich’s appointment that it was unclear whether his appointee would actually get the job.

Senate Democrats said they wouldn’t seat Burris, who in 1978 was the first African-American to win statewide office in Illinois. They told Blagojevich in a statement that anyone he selected would ’serve under a shadow and be plagued by questions of impropriety’.

Obama himself said Tuesday it is disappointing that Blagojevich ignored warnings from Senate Democrats about appointing a successor to his Senate seat.

‘Roland Burris is a good man and a fine public servant, but the Senate Democrats made it clear weeks ago that they cannot accept an appointment made by a governor who is accused of selling this very Senate seat,’ Obama said in a statement.

‘I agree with their decision, and it is extremely disappointing that Governor Blagojevich has chosen to ignore it.’

Obama added that the best resolution would be for Blagojevich to resign office and ‘allow a lawful and appropriate process of succession to take place. While Governor Blagojevich is entitled to his day in court, the people of Illinois are entitled to a functioning government and major decisions free of taint and controversy’.

Although Blagojevich, 52, has not commented publicly on the charges, his lawyer Ed Genson said the governor has done nothing wrong and does not intend to step down.

Burris, 71, also a Democrat, served Illinois from 1979 to 1992, first as state comptroller and later as attorney general. Earlier in December, he said that despite the scandal associated with the seat, he wanted the job.

He also appeared to support Illinois Attorney General Lisa Madigan’s efforts to remove Blagojevich from office, calling his alleged actions ‘reprehensible’.

Illinois Secretary of State Jesse White said Tuesday that Burris’ appointment will not be certified by his office.

But Blagojevich said at a news conference Tuesday that he is confident the US Senate will seat his appointment. ‘This is about Roland Burris, not about the man who appoints him,’ he said after announcing his choice in Chicago.

Calling Burris a ‘wise and distinguished senior statesman’ with ‘unquestioned integrity’, Blagojevich asked the media not to visit any of his political troubles on Burris.

‘Please don’t let the allegations against me taint this good and honest man,’ he said.

Burris said Tuesday that it’s ‘incomprehensible that the people of the great state of Illinois will enter the 111th Congress shorthanded.

‘I welcome the challenge that awaits us…have faith that the record I have forged in the past four decades, and I’m proud of the accomplishments as a public servant.’

Burris does not have to be formally approved by the Senate. But CNN cited associate Senate historian Don Ritchie to suggest that if there is a question about the appointment, the Senate could reject the appointment and immediately vacate the seat or vote to seat the senator pending an investigation by the rules committee or some other body.