Church leaders are distributing voter registration cards in the middle of services, and many are pledging caravans of “souls to the polls” to deliver the vote in a close race between President Barack Obama, the country’s first black president, and Republican challenger Mitt Romney.

Activists worry that new election rules in some states, from tougher photo identification requirements to fewer days of early voting, are unfairly targeting minority voters — specifically African-Americans who tend to vote heavily for Democrats.

“It has ignited a sense of urgency and collective power that we can take by engaging in the process,” said the Rev. Dawn Riley Duval, social justice minister at the Shorter Community A.M.E. Church in Denver. Colorado is one of the nine key states that doesn’t reliably vote Democrat or Republican and will determine the election, which is decided in state-by-state contests and not by nationwide popular vote.

In the biggest of the battleground states like Florida and Ohio, proponents of the new election rules deny they are aimed at suppressing the minority vote in hopes of helping Republicans win more races. Reasons for the rules vary between fighting fraud and purging ineligible voters.

But to some African-American leaders like the Rev. F.E. Perry, a bishop in Ohio’s Church of God in Christ, it’s as if the 1960s barriers to voting for many blacks, especially in southern states, have returned all over again.

“We’ve come too far to sit idly by and watch that happen,” Perry said. “We want to get souls to the polls. Whatever it takes to get them there, that’s what we’re going to do.”

In a close race, a state such as Florida — where a mere 537 votes decided the 2000 contest between Republican George W. Bush and Democrat Al Gore — could prove decisive.

In 2008, Obama won 95 percent of black voters and is likely to get an overwhelming majority again. He also won among Latinos, a rapidly growing constituency that also tilts heavily toward the Democrat in polls this year.

One organization, the faith-based PICO National Network, staged a “Let My People Vote Sunday” in September in which about 300 churches around the country held voter registration drives during services and recruited churchgoers to go out and register even more people. The goal was to sign up around 75,000 people, PICO policy director Gordon Whitman said.

In many states with early voting, the Sunday before Election Day in 2008 was a church-based political event in which minority congregations went en masse to polling places and cast their ballots. That year in Florida, 33.2 percent of all African-American voters and 23.6 percent of Latino voters cast ballots on that final Sunday, according to the Brennan Center for Justice at New York University.

In Ohio in 2008, Whitman said about 100,000 people voted during the last weekend before the election. A new Ohio law would have cut off early voting on the Friday before the election, but a federal judge declared it unconstitutional because some groups such as military personnel were exempted. The state is appealing that ruling.

This year in Florida, a new law eliminated early voting on that last Sunday. The law was also challenged in federal court, but a judge ruled in September there wasn’t enough proof that the change would harm African-Americans’ right to vote.