Political newcomer Mr Bill McBride is leading former US Attorney General Ms Janet Reno in the Democratic primary for Florida governor in an election marred by ballot-box problems reminiscent of the 2000 presidential election.
With votes counted in 90 per cent of precincts, Ms Reno, who served nearly eight years as attorney general under President Bill Clinton, trailed Mr McBride, a Tampa lawyer, by about 45-43 per cent. The winner will be the Democratic candidate facing incumbent Governor Jeb Bush, President George W Bush's younger brother, in the November general election.
But McBride's lead is shrinking as late votes come in from Mr Reno's stronghold in the south Florida counties of Palm Beach, Broward and Miami-Dade, where elections officials said polling station glitches might delay results for hours.
At 8 a.m. Irish time Mr McBride's lead was about 32,000 votes out of about 1.3 million cast.
Like the controversial election that sent the Mr Bush to the White House, this one was ensnared by problems with voting machines. This time it was modern touch-screen machines that forced poll workers at one Broward County precinct to hand out paper ballots and pencils.
As polls opened on Tuesday morning, new electronic voting machines were not working properly in dozens of precincts in Miami-Dade and Broward counties, two of the troublesome counties in the 2000 presidential election ultimately won by Mr George W Bush by just 537 votes.
The problems forced Governor Jeb Bush to order polls state-wide to stay open an extra two hours, until 9 p.m. (locally). But news of the extension apparently did not reach some precincts, where workers closed the doors at 7 p.m., angering waiting voters.
In Orange County, poll workers counted ballots by hand because scanners failed to read them. In Manatee County, a lightning strike caused a power outage that delayed results. In Miami-Dade, Florida's largest county, results were delayed when officials had to collect voting machines from more than two dozen polling stations because scanners had failed to record their votes.
A third candidate in the election State Senator Daryl Jones is lagging far behind.