A record 24 states hold primaries and party political meetings called caucuses on Tuesday, the result of a stampede by states to wield clout by moving up voting dates in the Democratic and Republican nominating races for the presidency. Hasty preparations for the Tuesday balloting provide ample opportunities for confusion and stalled tallies, voter advocates say.

Adding to the list of possible delays: expectations of record-breaking voter turnout in contests expected to be close. Many of the states that moved up primaries have never been involved in primary elections with meaningful impact, meaning past, later primaries had low turnout, said Ms Tova Wang of The Century Foundation think tank.

So on Super Duper Tuesday, or Tsunami Tuesday, as some have called it, American voters could face a number of difficulties - some new, some reincarnations of elections past.

In their haste to move up primaries, officials in some states appear to have overlooked ordinary facts of life, such as the weather and the advanced age of many poll workers.

Weather
Cold northeastern states including Connecticut and New York have encountered problems recruiting poll workers because many senior citizens, a sizable percentage of paid volunteers, are still south for the winter. Snow in the middle of winter also could have an impact, especially if there's bad weather on one end of a state and good weather on the other.

'There's been a lot of concern about the weather, and poll workers not showing up,' said Ms Wang. 'In states where a lot of their senior citizens are snowbirds, counties were having a hard time getting poll volunteers.'

A significant shortage of poll workers forced Linda von Nessi, clerk to the Essex County Board of Election in northern New Jersey, to advertise in newspapers.

'People were either in Florida or they didn't want to commit because of the possibility of cold weather,' she said. She has added 207 people to replace her diminished ranks.

'We've never had to hire that many new people,' she said.

Sunbelt states face trouble too
But even sunbelt states have faced troubles. As of Thursday, some California election officials were still recruiting poll workers on Internet sites.

Super Tuesday 'is really like a national primary,' said Mr Doug Chapin of electionline.org, funded by the private research organisation Pew Centre on the States. 'And the thing that's really striking about 2008 is we're still seeing a tremendous amount of change and a great deal of uncertainty' in the final days leading to Super Tuesday.

If state contests produce tight races, Mr Chapin said demands for recounts could abound. In New Hampshire, Democrats asked for a recount after the Jan 8 primary results differed widely from pre-election polls.

'If people are unhappy with the results, you may see the same kind of back-and-forth we saw in 2000,' Mr Chapin said, when Florida's recount went to the US Supreme Court and George W. Bush was declared the victor weeks after the November election.

In California, the most populous state, some election officials have already warned that vote counts will be far later than normal.

Los Angeles County Registrar-Recorder Dean Logan said record numbers of mail-in ballots and an anticipated deluge of voters could delay final primary results.

Shift from electronic machines to paper ballots
Election officials in 21 other counties, including several heavily populated ones, are struggling to implement what many consider a last-minute shift from controversial electronic machines to paper ballots. The change was mandated after state authorities decertified nearly all California's electronic voting machines, saying they were vulnerable to errors and sabotage.

In some areas, stacks of paper ballots must be driven to centralized counting facilities and fed by hand into optical scanners. Mail-in ballots, estimated at 40 per cent of the vote in Los Angeles County, also must be hand-fed into counting machines. A test run in populous San Bernardino County just east of Los Angeles showed that scanners could only count 10,000 votes per hour.

Some elections officials say that could lead to an increase in ballot errors, such as voting twice or leaving races blank. Without those machines at individual precincts, poll workers will not be able to catch mistakes until hours later at county headquarters.

'It's much more work for our poll workers,' said San Bernardino County Registrar Kari Verjil. 'It's very time consuming.' Mr Verjil has 4,000 touch-screen machines sitting in storage, for which the county paid US$16 million (S$22.7 million).

After Congress enacted the Help America Vote Act in 2002 - which was designed to prevent another election disaster - electronic voting was accepted by several states as the answer to cumbersome paper ballots, which must be fed into counting machines or tallied with optical scanners.

Electronic voting
Electronic voting - which accounts for about 40 per cent of voting technology used in the US, according to activist group Verified Voting - continues to spark controversy in other states as well.

For example, New Jersey officials failed to meet a state-ordered deadline to install paper printers on some machines to provide written proof of a voter's choice. So on Tuesday, voters will still use electronic machines - devices that voting activists say are unreliable and prone to error because they produce no paper record.

Producing identification at polling places is another troublesome issue, according to voters rights groups.

Identification
Georgia, which requires photo ID at precincts, faces its first statewide test of the law enacted after a long court battle. State officials have conducted public education campaigns, listing the type of photo identification that meets the state rule. They include: a Georgia driver's licence, even if expired; a military ID; an American Indian tribal ID; or a US passport.

Voters who lack such documentation can receive a free state photo ID. In some precincts, that identification can be issued at the polling place while would-be voters wait.

But that does little to appease civil rights groups and voting rights organisations that say the law disenfranchises minorities and the elderly - those most likely to lack such documentation.

The US Supreme Court is weighing whether a similar, but more restrictive, Indiana law violates the Constitution. A decision is expected this summer.

Arizona, too, faces criticism over state rules demanding photo ID at the polls - as well as requiring that proof of citizenship be shown when registering to vote. Unlike Indiana and Georgia, Arizona allows voters to produce two other forms of ID, such as utility and telephone bills, if they lack photo identification.

A coalition of citizens' groups filed suit against the law, saying it deprived residents of their right to vote. The suit is pending. Legal efforts by the coalition to temporarily block the law have failed.

Tuesday's primary will be the first election for national office in Arizona using the ID rule since it was approved by ballot initiative in 2004.

Arizona officials say the rule does not cause a hardship, it merely bolsters existing law that stipulates only US citizens have the right to vote.

Minority groups scoff at that.

'It's an unnecessary and very harmful obstacle to voter registration,' said Ms Nina Perales, an attorney with the Mexican American Legal Defense and Educational Fund, a party to the lawsuit.

'There is a disparate effect on Latinos. There are many people who don't have documentation that proves they're a citizen.' No matter what happens on Super Tuesday, there is an upside to voting this early in so many states, voting advocates say.

'If there really are problems, that gives states longer than they'd normally have to fix them before the November election,' said electiononline.org's Mr Chapin. -- AP