Election experts are warning that “unprecedented stress” on the nation’s polling infrastructure this year and a possible “wave of provisional ballots” being cast in battleground states could leave races up and down the ballot still undecided well after Nov. 4.

“I don’t have a very good feeling right now about Election Day,” said Ken Gross, an election law lawyer at Skadden, Arps, Slate, Meagher & Flom. “Provisional ballots could be the ‘hanging chad’ of the 2008 election, and if they are determinative, provisional ballots are going to take a lot of time to go through.”

The presidential campaigns of Sens. Barack Obama (D-Ill.) and John McCain (R-Ariz.) both declined to discuss Election Day legal strategies with Roll Call, but Gross and other experts predict that if the tally is close, the nation can expect a Florida-like recount debacle, referring to the one in 2000 that left Americans guessing about their new president until Dec. 12.

But instead of punch card machines that now reside in landfills, voting experts say the culprit this time likely will be electronic voting machines and provisional ballots, which voters in many battlegrounds could be forced to cast if their eligibility to vote is in doubt.

“I’m concerned about Florida, in part because they’ve changed their voting machines in some places three times since 2000,” Rick Hasen, professor at Loyola Law School in Los Angeles, said on Monday. “In the unlikely event that the election comes down to provisional ballots, it’s going to be a disaster. They’re the potential hanging chads.”

In addition to the Sunshine State, Hasen’s list of potential trouble spots includes Ohio, New Mexico and Colorado.

Colorado “had big problems in 2006 in Denver with their voting machinery,” Hasen said. “It’s the combination of battleground state and election administration overall, which is basically true in most states.”

Gross called Ohio “ground zero” for potential problems on Election Day, but Ohio Secretary of State Jennifer Brunner, a Democrat, said her office is ready for the influx of voters, staffing a voter help line and working with both parties in preparation.

“Our office on Election Day will be troubleshooting,” Brunner said in an interview late last week.

Brunner also said that the possibility of widespread voter fraud in her state on Election Day has widely been overstated in recent weeks, claiming that polling place fraud “is very detectable.”

“If you were to liken it to baseball, when you swing the bat is when you register to vote,” Brunner said. “When you get to first base that means you’re eligible to vote, and you can’t steal first base.”

Brunner also predicted that the centerpiece of the Republican Election Day strategy in Ohio will be to force as many voters as possible to vote provisionally, allowing lawyers a second crack at disproving a voter’s eligibility in the days and weeks following Nov. 4.

The U.S. Supreme Court last week ruled against the Ohio Republican Party, which recently sought to force as many as 200,000 Ohio voters to use provisional ballots because their names were flagged for misspellings and other inconsistencies in databases.

Provisional ballots allow Republicans “to segregate paper ballots and use legal maneuvering to pick [votes] off one by one to try and affect the outcome of the election,” Brunner said.

The Ohio GOP declined to discuss its Election Day legal strategy with Roll Call.

Gross agreed with Brunner that estimations of possible voter fraud likely have been overestimated. Still, that may not stop Republicans in Ohio and elsewhere playing up the specter of polling-place malfeasance in the hopes of catching a much-needed electoral break.

“There’s clearly been fraudulent activity in the registration process,” Gross said. “The saving grace will probably be that fraud in registration does not mean fraud in voting: If someone registered 17 times, it doesn’t mean that that person is going to vote 17 times — or even more than once.

“It’s hard enough to get people to go to the polls once, let along multiple times,” Gross added.

Like most election watchers, Gross predicts a huge voter turnout nationwide — perhaps 60 percent or more — and “unprecedented numbers of first-time voters.” And like Hasen, Gross predicted that malfunctioning electronic voting machines “will be put to the test.”

Gross also said that the recent foreclosure-driven migration in many areas of the country may add to voter eligibility challenges by Republican and Democratic lawyers alike.

Still, despite apocalyptic predictions from both sides of an Election Day meltdown, Hasen and Gross agree that even if the results of a few downballot races wind up being disputed, the national spotlight will only shine if the Obama-McCain contest is tight, which as of Monday appeared unlikely.

“The big issue is going to be whether it’s close or not — it’s like what Ed Koch said about HMOs: They’re fine as long as you don’t get sick,” Gross said. “If the election’s not close, then all the failings of the system will not come to the fore.”