Welcome to the first presidential election in which nearly every state must have a list of every registered voter. Here's the catch: if your name isn't on it, you may have trouble casting a ballot in this historic race for the White House.
The lists have already caused problems in New Mexico, Arizona and California, where people waited hours to choose a presidential nominee only to find they weren't listed as registered voters - or they weren't listed in the party of their choice.
On Tuesday, when folks line up in the crucial states of Ohio and Texas, election observers fret that similar snafus will confuse and delay primary vote counts that could help decide whether the Democratic nominee will be the first woman or the first black man to hold that title.
"It could be the sleeping giant in terms of voting problems," said Larry Norden of the Brennan Center for Justice at New York University's law school, which monitors election issues.
The problems stem from a federal law that was supposed to deter voter fraud. Under the Help America Vote Act, every state was required to have a computerized database listing all registered voters.
The deadline was 2006, which several states missed. Some of them, including New York and New Jersey, were sued by the Justice Department for not having databases up and running.
This year marks the first time the lists are being used in presidential contests, and every state except North Dakota (which has no registration system) has some interim or permanent system in place. But there is great confusion about what to do if a voter's name is missing, or shows up under the wrong party affiliation, election advocates say.
In states such as New Mexico, where Super Tuesday caucuses were plagued by long lines and registration issues, it took nine days to tally votes. Part of the problem stemmed from an avalanche of so-called "provisional" ballots - which take longer to count - given to voters for a variety of reasons, including being dropped from registration lists. In California, the Super Tuesday final tally has yet to be certified because of large numbers of impromptu ballots cast by voters whose names weren't on the list, as well as other poll problems.
The voting law was designed to produce accurate lists of eligible voters that could be coordinated with other government databases, including drivers' license and Social Security rolls. It allowed to states to purge clutter caused by multiple registrations and to eliminate those ineligible to vote - the dead, for example, and in some states, convicted felons.
In 2005, a Seattle woman registered her Australian shepherd-terrier to vote under the name Duncan M. MacDonald - via mail, with a phony utility bill submitted as identification. She did it, she said, to show how easily noncitizens could register.
Some election officials went too far, according to voting activists, and interpreted those requirements to mean that registration applications should be denied when they don't match government data.
In Florida, the state NAACP chapter and others sued election officials, saying more than 14,000 people, most of them minorities, have had their registrations wrongly denied or delayed since 2006. According to the federal lawsuit, many of the discrepancies were caused by transposed numbers and confusion over minority names that results in data-input error. Hispanic names can contain maternal and paternal family names, Haitian and Hispanic names can be hyphenated and blacks' names can contain unique spellings and apostrophes, the suit said.
In December, a federal judge ordered election authorities to stop enforcing the 2-year-old law, saying there is proof that it has resulted in "actual harm to real individuals." The case is on appeal.
"Depending on the decision, it could be an important issue in the general election," said Justin Levitt of the Brennan Center. Florida, which decided the presidency after experiencing recount havoc in 2000, "obviously was important, is important and will be important in any election," he said.