President-elect Barack Obama’s move from Capitol Hill to the White House leaves Illinois with only one member in the U.S. Senate; Sen. Dick Durbin. While Obama was chosen by millions of voters across the country to be elected to the nation’s highest office, the decision of his replacement in the Senate will lie in the hands of one man—Illinois Gov. Rod Blagojevich. And many are sounding off about how the governor will decide.

Michael L. Mezey, a political science professor at DePaul University who specializes in American politics and Congress, said Blagojevich can pick anybody from the state to be the new senator.

“[Technically] the governor can appoint anybody that fits Senate qualifications: 30 years old and a state resident. There is no other criteria,” Mezey said. “One would hope the person is qualified for the job, but political considerations have been taken in, as well. There are so many different directions the governor could go.”

Dave McKinney, the Springfield bureau chief of the Chicago Sun-Times, said he heard many rumors on who the replacement senator would be.

Tammy Duckworth, the director of the Illinois Veterans’ Affairs Department, is a favorite of Blagojevich, said McKinney, who reports on the governor and the Illinois Congress. Duckworth, a former U.S. Marine who lost both of her legs while serving in Iraq in 2004, has since spoken out against the war.

But McKinney said there are other potential choices as well. Luís Gutiérrez, a 15-year congressman from the state’s 4th District and the first Hispanic-American to be elected to Congress from Illinois, has spent a lot of time in Washington, D.C. working on legislation for immigrants rights. Jesse Jackson Jr., who has been the congressman from the 2nd District for 13 years, is also being considered.

Jackson has been recognized nationally due to his involvement in his father’s movement for civil rights movement and has been an avid supporter of Obama during the former senator’s presidential bid. But considering the governor’s low popularity ratings, nothing is certain about his pick, McKinney said.

“It is hard to gauge, because the governor hasn’t said much,” McKinney said. “He most likely will turn to somebody who he’s close with, that has stuck with him. It’s sort of a mystery right now.”

State law gives no written deadline for when a replacement must be in office. Brian Williamson, a spokesperson for Blagojevich, said the governor has no time restraints to make his pick. That means Obama’s former senate seat could stay vacant for a while, even after the former senator has taken his place in the Oval Office.

“There is no specific timeline, but obviously in the best interests of everybody involved it won’t take too long,” Williamson said. “It’s all speculative at this point, we’re looking for the best person for the job. It will be given a lot of thought.”

McKinney pointed out it would be in the new senator’s—and also the state’s—best interests to appoint the new official soon.

“You’d think he wants to replace Obama quickly to give that new senator seniority over all the newly elected officials that are sworn in,” McKinney said. “It would defy reason to allow the seat to remain vacant.”

The new Illinois senator would fill in during the remainder of Obama’s term, which goes through November 2010. The last time a governor to replace a senator who became a member of the executive branch was in 1993, when Tennessee Gov. Ned McWherter chose Harlan Mathews to replace Al Gore after he was elected as Bill Clinton’s vice president. However, Mathews was in office for one year before being voted out.