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Whether Democrats regain control of the Senate could hinge on whether Sen. Jon Corzine (search), D-N.J., ignores or embraces state-party calls for him to give up his seat and seek the job being vacated by embattled Gov. James McGreevey (search).

Republicans hold a 51-48 Senate majority, but the one independent — Vermont's Jim Jeffords (search) — votes with the Democrats, so the party needs to pick up two seats to gain control. That's considered a possibility, albeit a tough assignment for November.

Should Corzine give up his seat before the election, that could allow the Republicans an opportunity they wouldn't otherwise have to add to their majority. Still, if Corzine then ran in a special election for governor and won, he would appoint the person to fill his Senate seat until the next general election. The person he would most likely select is Rep. Robert Menendez (search), D-N.J., who has made it known he would like to be a senator.

"This would be a way to slot both races," said John Fortier, an analyst for the American Enterprise Institute who studies Congress. It would leave the Senate balance just the way it is going into Election Day.

A big question then: Who would be the Republicans' candidate in a special election for governor?

"Who do the Republicans have with the name recognition and funding that Corzine has?" asked Fortier. Corzine, a multimillionaire, used more than $60 million of his own money to run for the Senate in 2000. "I think he would be well-suited to win it," the analyst said.

Possible challengers the Republicans might like to turn to would include two former governors — Thomas Kean (search) and Christie Whitman (search).

Roger Bodman, a Republican strategist and former Kean aide, said he doubted Kean would run. Kean could not be reached for immediate comment. A spokesman for Whitman did not return a telephone call for comment.

The tumult in New Jersey was created last week when McGreevey disclosed he was gay and said he would resign. Corzine has said he has no plans to abandon his Senate seat, but state Democrats are putting heavy pressure on him, seeing the former business executive as their best hope to hold on to the governor's office.

What he does may depend on when McGreevey steps down.

McGreevey wants to leave office Nov. 15 — two weeks after the election and a time when Corzine will know whether Democrats will have a majority in the new Senate. But some state Democratic leaders are pushing for McGreevey to leave immediately, saying three months of a wounded lame duck are too many.

If McGreevey can stay in office until at least Sept. 3, the election to replace him wouldn't occur until November 2005, the next general election. The New Jersey state Senate president, a Democrat, would be the acting governor. But if McGreevey resigns before Sept. 3, a special election would be called for Nov. 2.

The Democratic National Committee and presidential candidate John Kerry's campaign have publicly kept their distance from the New Jersey situation, but they're watching it closely.

Senior party officials in Washington said Monday they want to avoid a special election that not only could cost them Corzine's seat but also muddle the presidential race in New Jersey, where polls suggest Kerry has a comfortable lead over President Bush.

Corzine, 57, entered the 2000 Senate race with no political experience. The former co-chairman of Goldman Sachs Co. had been chosen by the state's Democratic Party to run for an open seat. Corzine won and his business experience was quickly tapped by the Democrats. In December 2002, he was named the party's Senate campaign committee chairman.

The New Jersey governorship has been called the most powerful in the country because there is no lieutenant governor and the governor appoints his entire cabinet.

Ross Baker, a political science professor at Rutgers University, said that autonomy may be appealing to Corzine.

"I think Corzine would like to be influential in the Senate but it will be many years before he would get a chairmanship," Baker said. "The governor's office may be someplace where he can make a bigger influence."

If Corzine does decide to run in a special election, Republicans say that would signify the senator's acknowledgment that Democrats will once again be the minority party in Washington.

"One could conclude that their chances are slim in regaining the Senate and that he does not have his heart in the job and wants another one," Bodman said.