SPRINGFIELD - Despite stern warnings his pick will be rejected, a defiant Gov. Rod Blagojevich named former Illinois Attorney General Roland Burris to Illinois' vacant Senate seat Tuesday. | Burris has been around Illinois politics quite some time | Quotes: Reaction to Burris's appointment | Obama: Burris shouldn't be seated in Senate

The surprise move ignited a firestorm of controversy, including threats from Democratic leaders at the state and national level to block the embattled governor's action.

At the same time, at least one African-American leader said it would be wrong to stand in Burris' way given that Burris would be replacing Obama as the lone black member of the Senate.

"It has tremendous national importance," said U.S. Rep. Bobby Rush, a Chicago Democrat.

Blagojevich is accused by federal prosecutors of plotting to sell President-elect Barack Obama's vacant U.S. Senate seat in exchange for money or a higher paying job. The accusations jumpstarted impeachment proceedings in the Illinois House and led to calls to strip Blagojevich of his appointment powers.

Blagojevich said it is his duty to fill the vacancy.

"Don't allow the allegations against me to taint this good and honest man. He will be a great United State's senator," Blagojevich said.

The naming of the 71-year-old Democrat comes after Blagojevich's defense attorney said the governor wouldn't choose a replacement for Obama. But, despite his mounting legal woes and his damaged political image, Blagojevich still holds the power to fill the opening.

Since his arrest, Blagojevich has continued to go to his office in downtown Chicago, where he has signed legislation and worked on requests for clemency. He said last week he would not resign.

Burris, who would serve out the remaining two years of Obama's term if his appointment goes through, said the governor's woes shouldn't rub off on him

"I have no relationship with that situation," said Burris, who was comptroller from 1979 to 1991 and attorney general from 1991 to 1995.

"I am humbled to have the opportunity," Burris added. "I will uphold the integrity of the office."

However, Burris faces an uncertain path to Washington D.C.

Illinois Secretary of State Jesse White said Tuesday he would refuse to certify the appointment when it reaches his desk.

"Although I have respect for former Attorney General Roland Burris, because of the current cloud of controversy surrounding the governor, I cannot accept the document," White said in a statement Tuesday.

Democratic leaders in the U.S. Senate, including U.S. Sen. Dick Durbin of Illinois, said they would not seat Burris - a two-time statewide officeholder who has spent recent years as a lobbyist.

"Anyone appointed by Gov. Blagojevich cannot be an effective representative of the people of Illinois and, as we have said, will not be seated by the Democratic Caucus," the statement said.

Durbin called Blagojevich's maneuver a "mistake."

"It is an act of political defiance," Illinois' senior senator said.

In a statement, Obama sounded a similar note.

"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. I agree with their decision," said Obama, who is vacationing in Hawaii.

Democratic state lawmakers said Burris would be an OK replacement for Obama, but said Blagojevich shouldn't be the one doing the choosing. Rather, they want to see him booted out of office, allowing Lt. Gov. Pat Quinn to take over and make the appointment.

"I think it is unfortunate for Roland's part because if Pat Quinn had appointed him it would be a whole different matter," said state Rep. John Bradley, D-Marion.

State Rep. Dan Brady, R-Bloomington, compared Blagojevich's behavior to a rabid dog.

"It's kind of like you've got someone cornered. He's lashing out," Brady said.

House Minority Leader Tom Cross, R-Oswego, said he initially thought Blagojevich's decision was a "sick" joke.

"He's kind of angry at the world," Cross said.

Although Burris resides in Cook County, he was born in Centralia and often cited his southern Illinois roots on the campaign trail.

After Obama's Nov. 4 win, Burris lobbied for the job, which he had also sought in 1984 when he ran unsuccessfully for the post against the late Paul Simon.

In a statement, Illinois GOP leader Andrew McKenna said Democrats should have stripped the governor of his power to appoint when lawmakers met in an emergency session Dec. 15.

"Because they went back on their word and refused to strip Blagojevich of his appointment power and pass a special election, Illinois Democrats have created yet another constitutional crisis for Illinois," McKenna said.

McKenna added that the appointment is "is another embarrassment for the people of Illinois."