ATKINS: PREZ HITS TRAIL,

WASHINGTON — President Obama has embarked on a dizzying stumping spree for Hillary Clinton this week, just as early voting returns show a lag in the black vote that helped propel him to victory in 2012 and 2008.

“Work as hard for her as you did for me,” Obama implored supporters at a rally yesterday in Columbus, Ohio — one of several stops the president will make today, tomorrow and Friday in Ohio, Florida and North Carolina, all states that are not only crucial battlegrounds, but also places where early voting turnout among black voters is down from the last two presidential cycles, according to data from the U.S. Elections Project.

A number of factors, including the absence of a black candidate at the top of the ticket and the negative tone of the presidential race, are contributing to the apparent decrease in enthusiasm among black voters this year, experts said.

“We are living in one of the most politically toxic and racially divisive times in a generation,” said Glynda C. Carr, political strategist and co-founder of Higher Heights, a nonpartisan group aimed at boosting black women’s political engagement.

But experts also noted a number of state and local laws in Ohio, North Carolina and other states that rolled back the number of early voting days and sites.

In 2012, 70 percent of black voters cast votes early in North Carolina, as compared with 50 percent of the total voting population. Fewer early voting days lead to longer lines, particularly on weekends, which has a disproportional effect on black voters, according to data compiled by the ACLU, which joined other groups in a lawsuit against North Carolina.

While appearances by high-profile surrogates like the president and Michelle Obama draw excitement and media attention, they don’t alone send more voters to the polls. But they do motivate grass-roots organizers who are key to get-out-the-vote efforts in the days leading up to Election Day.

“The most active voter motivation efforts happen the last weeks of the campaign,” said Andra Gillespie, an Emory University professor specializing in political mobilization and race. “It may be difficult to change people’s minds now, but this is prime time for getting out the vote.”

Appearances like Obama’s “activate the network,” Carr said. “We don’t go to the polls alone. We bring the people in our houses, and on our block, and in our churches and from our sororities.”