Obama’s campaign made an unprecedented push for Democrats to vote by absentee ballot this year because the Republican governor and Legislature reduced the number of days for in-person early voting, which Democrats typically dominate.

In addition to cutting early voting days, lawmakers lengthened the ballot by printing the full text of some constitutional amendments. That led to long lines at some polling stations that didn’t have enough capacity.

The process of reviewing the ballots is nonpartisan, but partisan and racial disparities emerged.

Hispanic Republicans — who make up 72 percent of the GOP in Miami-Dade — are the most likely to vote absentee and the least likely to have their ballot rejected, with a cancellation rate of just 0.56 percent, according to a Miami Herald analysis.

Black voters registered as independents in Miami-Dade had the highest rejection rate: 2.35 percent.

Overall, black voters had the highest (1.2 percent) and Hispanics the lowest (0.79) rejection rate.

University of Florida professor Dan Smith, who plans to soon publish a Florida-voting study with Dartmouth College professor Michael Herron, said the data indicate that voters familiar with the requirements of absentee-ballot voting are more likely to have their votes counted. Still, he said, while it might be easier to vote by absentee ballot, it can be tougher to get that vote counted.

“Absentee ballots are processed and verified using different standards than regular ballots,” Smith said, “and as such, are routinely rejected at a higher rate by county supervisors than ballots cast during the early voting period or on Election Day.”

Election Day and early in-person voters can personally protest if they encounter a problem at the polls and, if need be, can cast a provisional ballot. But absentee voters take a leap of faith when they drop the ballot in the mail. They have to trust the mail service to deliver their ballot on time and the county elections workers, who have to ensure that the ballots were lawfully cast.

Had the four Miami-Dade and Broward absentee-ballot voters who died before Election Day voted early in person, their votes would have counted. If their absentee ballots had been received by the elections offices before their deaths, the votes could have been counted as well.

A large number of voters said they did not know their ballots were rejected until they were contacted by The Miami Herald. The county says it is notifying those voters by mail.

Miami-Dade’s deputy elections supervisor, Christina White, said the county verified that the deceased voters — and not some fraudster — had filled out their absentee ballots, which can be the most fraud-prone voting method.

White said the county has to follow state law, which says absentee ballots mailed within the United States have to reach the office by 7 p.m. Election Day, and that overseas ballots must be in five days after that.

White acknowledged that a number of voters complained they didn’t get their ballots soon after they were ordered. She said the county sought help from the state and the U.S. Postal Service. But there was only so much the county could do. The postal service said it’s not to blame.

Then there’s the matter of signature-verification on ballots to stop fraud.

“When you go to vote on Election Day, you have to provide an ID. We don’t have that ability with an absentee ballot,” White said. “The only way to do that is to compare the signature. Does it happen that signatures change over time? Yes. We try to tell people to update their signature.”