As Americans prepare to go to the polls to choose the country's next president, the two main political parties also have been gearing up for potential voting problems that could emerge during and after the balloting.  Steps taken by both the Republican and Democratic parties include sending thousands of partisan monitors to be present in the balloting centers on Election Day and mobilizing thousands of lawyers to be prepared to challenge any perceived irregularities. 


Both the Republicans and the Democrats have strong concerns about the integrity of this year's presidential election.


For the Republicans, the main issue is voter registration fraud.  On the other side, Democrats say a higher turnout works in their favor and charge the Republicans with trying to limit the number of legitimate votes that are counted.


Republican party chairman Ed Gillespie told NBC's Meet The Press he is concerned about a host of voter registration problems.  These include having more people registered to vote in certain counties than are actually eligible and voters registering under false names.


To address some of these issues, immediately and on the spot, the Republican party has hired thousands of workers to be present in polling centers in key U.S. states on Election Day to challenge voter eligibility.  The apparent target of this drive is the hundreds of thousands of newly-registered voters, many of whom are eligible to cast provisional ballots because their names are not yet on the registration lists.


"Now, somebody could go and register one place, go and cast provisional ballots in three or four other precincts," said Mr. Gillespie.  "We can't count those votes.  If somebody votes four times, my one vote is diminished, and it's cancelled out by those three or four votes.  We've got to make sure this is an honest election."


Provisional ballots were mandated throughout the country by the 2002 Help America Vote Act, which was passed into law following the controversy over ballot results in Florida, in the 2000 presidential election.


The law requires that all states allow any citizen not on the voter registration list to cast a provisional ballot after showing identification and signing a written affirmation of eligibility.  Federal courts have ruled that in order for the votes registered by provisional ballots to count, though, voters must cast them in their correct precincts.


Democrats oppose Republican plans to challenge people over voting eligibility, saying this could delay the process unduly and discourage many people from even casting a ballot.  Democratic party chairman Terry McAuliffe also accused the Republican party of trying to disqualify valid votes.


"The goal of the Democratic Party is to make sure that everyone who has a right to vote in this country can go to the polls, and can vote," he said.  "We know what the Republicans are going to try to do.  They're going to try and disenfranchise voters.  We want everybody to vote."


The hotly-contested state that is getting much of the attention this year is Ohio, which has about eight million registered voters.


"We have approximately 650,000 new registered voters this election, from the previous year, so we have seen a large influx of new voters," said Dana Walch, in the office of the Ohio Secretary of State. 


Mr. Walch says 30,000 names on the voter registration rolls have already been challenged, and that county boards are holding hearings to determine the status of those people.  But he added that these people will still be allowed to cast a ballot on Tuesday.


"We've instructed the boards of election in all these cases to provide the voter, if they come to vote, with a provisional ballot, so that they can cast a ballot on election day,"  he added.  "Then, if they're determined to be a legally qualified elector, that ballot's going to count."


About 106 million Americans cast votes for president four years ago, and experts predict this year's turnout will be much higher.  Mary Boyle is from Common Cause, a non-partisan organization that promotes government accountability.  She says with so many new voters, there are bound to be problems. 


"Well, there are 10-15 million new voters this year, and a close presidential race," she noted.  "We are expecting problems.  We're seeing them already.  There are challenges and reports of voter irregularities in many states.  It stands to reason that we'll hear the most about swing states (where the vote is very close) like Ohio and Pennsylvania and New Mexico."


She says she worries that partisan monitors at the polls could scare legitimate voters away.


"We're very concerned with any situation that would make people feel intimidated and not want to go, not only prevent them from voting, but just kind of, I mean, prevent them from voting, discourage them from even going to the polls," she added.


Memories of the 2000 election have galvanized both parties to be prepared this time.  Both sides have thousands of lawyers on the ground in states across the country, ready to spring into action should there be questions about close vote tallies.


"This could be the most litigious election in American history," said veteran poll watcher Curtis Gans.


Mr. Gans heads the non-partisan Committee for the Study of the American Electorate.  He says he believes most voters have strong enough feelings about this election, though, and won't be intimidated from casting their ballots. 


He adds that he is also certain each party will be closely watching the other side to try to guard against irregularities.


"I feel that this election has emotional underpinnings that will deter few people who want to vote from going out to vote," he added.  "I'm not sure of that, but where people are concerned about Republican intimidation, I'm sure there will be Democrats with tape recorders.  Where people are concerned about false names, I'm sure there will be Republicans scrutinizing names.  But I think people will vote."


Mr. Gans says his biggest hope is that there is a clear victor on election night.  He doesn't care which candidate wins, he says, so long as the results are decisive.