Updated

Only minutes after hearing that Sen. Paul Wellstone had been killed in a plane crash, elections experts were cracking open Minnesota's election law books to see how his death will affect who holds the seat.

According to Minnesota elections law, when a senator dies between four and 16 days from an election, the state Democratic Party can nominate a replacement candidate, basically putting a sticker over Wellstone's name on the ballot. The deadline to do this is next Thursday.

Minnesota Gov. Jesse Ventura hopes to decide by Monday -- if not sooner -- on how to handle the vacancy.

Fox News has learned that Wellstone's two sons have encouraged former Vice President Walter Mondale to run. Mondale, a former vice president and Minnesota senator, is now an attorney in Minneapolis. He turns 75 in January.

Election Day is Nov. 5, and some think that Republican candidate Norm Coleman's chances of election are improved with the loss of Wellstone, since his approval ratings are high enough to surmount the party split. As of last week, a poll showed Wellstone with a slight lead over his Republican opponent.

But Democrats would like to keep the Senate in Democratic hands. Coleman, a former mayor of St. Paul, could win the seat to erase the one-vote Democratic majority.

That means finding a quick replacement.

Ventura's spokesman, John Wodele, said he has the impression that Ventura will choose a Democrat to succeed Wellstone. Wodele said his feeling is that Ventura does not want to upset what would have been the normal course of events. For example, if Wellstone had been defeated in November, he still would have been able to vote in the Senate until a new senator was inaugurated in January.

Minnesota Attorney General Mike Hatch, a Democrat, said state statutes require Wellstone's name be removed from the ballot and be considered a vacancy. But this may be a logistical nightmare, given that many of Minnesota's 81 counties use different types of ballots.

Hatch said absentee ballots with Wellstone's name on them will be counted for Wellstone. Votes for Wellstone will be worthless and not counted for the Democratic replacement. That could help Coleman.

About 100,000 absentee ballots have been requested, which will amount to about 5 percent of the 2 million votes expected to be cast.

Both parties are worried about landing in court and are preparing for the possibility.

Republicans say they are already in a "Florida style precount" mode. Attorneys and political operatives from both parties are flying into Minnesota from Washington. On absentee ballots, both parties are preparing for possible litigation.

Democrats fear voters who cast absentee ballots for Wellstone will be disenfranchised. But to discount 5 percent of the ballots altogether would disenfranchise voters in all the other races and that percentage could be determining factors in other contests, such as the governor’s race.

Meanwhile, all campaign ads have been halted. Wellstone’s funeral likely will be scheduled for Wednesday.

So far, Mondale has been suggested as a possible party replacement by party leaders, said Democratic St. Paul Mayor Randy Kelly.

"I am sure that is something that would be embraced readily at this point by many Democrats," Kelly said, though he said no one is yet having serious discussions.

Mondale last was actively involved in politics when he ran for president against President Ronald Reagan in 1984.

"If Walter Mondale wants to go back to the United States Senate, the Democrats select him in one way or another, he will be the pick," said former Ohio Republican Rep. John Kasich.

Other replacement options include Skip Humphrey, son of the late vice president, Hubert Humphrey, former Minnesota Viking and current state supreme court justice Alan Page and Mondale's son ,Ted, who ran briefly but dropped out of the 1988 governor's race that Ventura won.

Their names and a handful of others were in circulation within hours of the plane crash.

Democrats could name a replacement candidate within 36 hours. However, Democratic legal eagles are trying to ensure that Ventura doesn't stand in the way of that plan.

According to state law, Ventura, an independent, has the option, at least until Election Day, of appointing his own replacement to fill out Wellstone's term, which lasts until January.

"Whoever wins on Nov. 5 would supercede the governor's appointment immediately," said Allan Weinblatt, a Minnesota elections law expert.

Weinblatt said that whoever wins the election on Nov. 5 would be sworn in immediately to establish seniority in the Senate.

But Fox News political analyst William Kristol said that's not his interpretation of the law. He said Ventura could still appoint someone to fill out the remainder of Wellstone's term, a conflict that has Democrats nervous that the unpredictable maverick could appoint someone not to their liking.

"I assume that what Gov. Ventura will do is appoint whoever wins the election, certainly if it is a Democrat, to fulfill Wellstone's term. There is a lame-duck session so it's not unimportant for Minnesota to have a senator during that session." Kristol said.

"At this time, I will only state this unequivocally and absolutely, I will not appoint myself," Ventura said Friday. "That is the only question on that issue that I will address today, that it will not be me."

Kristol said he doesn't think Ventura would deviate from the Democratic script.

"I would be very, very surprised if Gov. Ventura appointed anyone over the next 10 days before Election Day," said Kristol.

The Associated Press contributed to this report.