Sisters Mercy Davis, 20, and Marissa, 18, were so energized to cast a ballot in their first presidential election that they stood in line before sunrise, waiting for the early voting polling site to open Saturday at the Model City Library in Brownsville.

Alberta Corbar, 91, came in her wheelchair, brought to vote by grandson Cunny Ivory and his wife, Barbara.

A few miles to the north in Broward County, the line of early voters wrapped around the Hollywood Library.

From Government Center in downtown Miami to the Coral Gables library to the West Dade Regional Library in Westchester and points south, voters took advantage of the cooling weather and, inspired by the heated presidential race, made their picks on a ballot that’s one of the longest in South Florida history and packed with divisive issues.

[Check out the Herald Editorial Board’s recommendations for constitutional amendments, proposed charter changes in Miami-Dade, the schools bond referendum (Yes!) and candidate picks in Broward and Miami-Dade, in Issues & Ideas or go to miamiherald.com/opinion.]

The pictures of Florida’s first early-voting day, taken by Herald photographers and tweeted by reporters, speak to voters’ hopes and fears in this election, in a nail-biter between President Obama and former Gov. Mitt Romney.

Anxiety levels are high among Democrats after GOP-led legislatures from Wisconsin to Pennsylvania passed laws dramatically shortening early-voting days (Florida, Ohio), making it harder for volunteer groups like the League of Women Voters to register people (Texas, Florida) or imposing photo I.D. requirements, which have been blocked by the courts in states like Wisconsin.

In just the past two years, more than 30 states have enacted laws, or are considering bills, to require more hurdles before you can exercise your right to vote. The intent is to prevent voter fraud, which no one would disagree with, but it’s a “cure” without a disease.

The fraud, in Florida and other states, has been in absentee ballots, where ballot brokers, the so-called boleteros, mine senior centers, public housing and nursing homes to “help” the elderly fill out their ballots and deliver for the candidates paying them.

Because absentee ballots skew in Republicans’ favor and early voting results tilt toward the Democrats (in historic numbers for Obama in 2008), Republican legislators in red states weren’t about to crack down on absentee ballot abuse.

Florida, ground zero for the 2000 hanging chad debacle in which Al Gore won the popular vote but lost the presidency in Electoral College votes that hinged on Florida’s marred election, went for Obama in 2008. But polls have shown Romney picking up momentum.

For Republicans, particularly elderly Cuban-American voters who fled communism, the high anxiety revolves around right-wing claims that Obama is a “socialist” poised to destroy all that Americans cherish.

So when I spotted in a photo Miami voter Tony Abreu’s sign, “Tell yo mama to vote for Obama,” I chuckled after recoiling in horror. Try telling my mama, Tony. I won’t. I know better.

If there are still people undecided after the three debates and Obama’s governance the past four years and Romney’s campaigning for the presidency the past six, then heaven help us. When it comes right down to it, voting at its most basic comes from the gut.

My mother and her generation may be better off under an Obama administration as far as Medicare and Social Security goes, but their gut tells them he’s not to be trusted.

For African-American voters whose parents and grandparents risked their lives to march in the South for civil rights to put an end to Jim Crow laws, their fears about the GOP seeking to disenfranchise them and suppress their votes are more than a gut call. They’re justified.

Shady things have been happening in the 10 battleground states. Voters in 23 Florida counties have reported receiving an official-looking letter from the elections supervisor stating, “please stop by our main office with any original documentation that demonstrate U.S. citizenship” or their names would be removed from the voting rolls. It’s a fake letter from Seattle that’s under investigation.

In Arizona’s Maricopa County, where Sheriff Joe Arpaio has made a national name for himself for stopping Latinos “driving while brown” to ask for their papers, the real county elections office mailed out ballot information in Spanish telling voters Election Day was Nov. 8, two days after it’ll be all over.

Oops, a mistake, Maricopa County elections officials maintain.

The gut of this independent voter tells me we’re in for another showdown.