Election officials in heavily Democratic Palm Beach County began a hand recount of more than 430,000 ballots last night after the Florida Supreme Court said the county could proceed with a tally that Vice President Al Gore believes will prove that he received more votes in Florida than Texas Gov. George W. Bush.

The court's interim ruling was a setback to Bush, as well as to his campaign co-chair in the state, Katherine Harris, the Florida secretary of state, who has said that only votes tabulated by last Tuesday should count. Harris had told Palm Beach County that it could conduct a hand recount only if it could prove that its vote-tallying machines had malfunctioned.

But the more critical ruling should come this morning, when a state circuit judge in Tallahassee will say whether Harris overstepped her authority on Wednesday, when she declared that she would not include any results of hand counts in the state's final vote tally. The winner of Florida's 25 electoral votes would almost certainly become president.

Harris said she would officially certify the Florida election results tomorrow, after about 2,000 overseas absentee ballots are counted.

Confident that those overseas ballots will expand the governor's razor-thin, 300-vote official lead in Florida, the Bush campaign did its best yesterday to reinforce Harris' contention that tomorrow's tally would be final and that the results of the hand counts won't be included.

To that end, Bush's campaign chairman, Don Evans, said the Texas governor would not seek a recount in Iowa, where Gore prevailed by only 4,047 votes. The state's seven electoral votes would likely make no difference in deciding who will be the 43rd president of the United States. But Evans tried to make Bush's actions in Iowa a lesson for Gore - and the nation.

"Both sides waged vigorous campaigns in Iowa," Evans said. "The results are exceptionally close, but Governor Bush believes the time has arrived for our nation to begin the process of moving forward.

"A concluding deadline arrives tomorrow night at midnight in Florida, as the final votes come in from the overseas ballots," Evans continued. "Once these votes are counted, we will know the final result of Florida's election and the nation's election. Win or lose, this election will be over."

The slender margin in Iowa is actually not that comparable to the minuscule gap in Florida. Gore defeated Bush by three-tenths of 1 percent in Iowa, whereas Bush's 300-vote edge in Florida amounts to a lead of just five one-thousandths of 1 percent. Were the margin in Florida comparable to that in Iowa, Bush's lead in the Sunshine State would be more than 18,000 votes.

And the momentum may be in Gore's favor - at least temporarily. A hand recount of 588,000 ballots began yesterday in Broward County. And with 86 out of 609 precincts completed, the vice president had picked up 21 votes. At that rate, Gore could pick up more than 100 votes - not enough to swing the election but, Gore aides hope, enough to maintain public doubts that Bush actually won Florida.

Gore aides said yesterday that they never expected to gain more than 100 votes in Broward. But based on the results of a sample hand count in Palm Beach County, those aides say, the vice president could gain as many as 2,000 votes there in a recount that officials said could take up to six days.

That is because the county's "butterfly ballot" - on which Gore's name appeared nearly side by side with Reform Party candidate Patrick J. Buchanan's - may have prompted some voters to indicate their choice in novel ways, such as circling their candidate or writing in a name by hand. Such ballots might have been invalidated in the machine counts but perhaps would be accepted in the hand count as votes for Gore.

"Palm Beach has always had the numbers," a senior Gore campaign aide said yesterday.

Gore campaign attorneys insisted that the Florida Supreme Court ruling could be the first step toward Gore's capturing the state. If Harris is presented with actual recounts, and rejects them, the Gore campaign would seek a court order to include the new numbers in Florida's final count.

David Boies, a lawyer for Gore, asserted that the Florida Supreme Court, whose members were all appointed by Democratic governors, appeared to indicate that the recounts should be considered in the final tally.

"I think it's very unlikely that the Florida Supreme Court would have directed that these recounts go forward if all they meant to do was to preserve the votes for history," Boies said.

But Bush campaign officials dismissed the ruling's significance, saying that the Florida Supreme Court had not ruled on the merits of Harris' argument against the legitimacy of hand counts. It simply let the hand counts go forward.

"Now we will have some counting, that's true," allowed former Secretary of State James A. Baker III, who is Bush's point man in Florida. "But I don't think you can characterize it as a setback."

Harris, who campaigned for Bush, is still expected to certify a Bush victory on Saturday, giving him the state's 25 electoral votes, and possibly the White House.