NEW ORLEANS -- Mary Landrieu is one of the most vulnerable Democrats in the U.S. Senate, and her chances of re-election this fall could come down to her ability to turn out African-American voters like Barbara Brown.
Standing outside Franklin Avenue Baptist Church in the crisp white suit that marks her as an usher, Ms. Brown pursed her lips at the mention of months of television ads that have already aired attacking Ms. Landrieu and her vote for the national health care law, which Ms. Brown sees as an unfair rebuke of President Barack Obama.
"Just disgusting -- enough to make you sick to your stomach," Ms. Brown said. All that criticism of Ms. Landrieu for "standing on the president's side," she said, has made her even more committed to supporting the three-term senator this fall and encouraging others to do the same.
"I like what she said," Ms. Brown added, using a Landrieu line that appeared in one of the ads critical of the senator's position on the health care law: "She says, 'If I had to do it again, I would do it again.' "
Few senators up for re-election this fall face a more complex balancing act than Ms. Landrieu, who hails from a state that Mr. Obama lost by 18 percentage points in 2012. She is aggressively pursuing independents and Republicans, who have been key to her past wins but are unhappy with Mr. Obama's performance. But central to her chances is reversing the traditional midterm drop-off in voting by black Louisianans, who make up 31 percent of the electorate.
Ms. Landrieu's task reflects a larger imperative for Democrats this year and in 2016: to guarantee a massive turnout by the party's most loyal voters when the nation's first African-American president is no longer anchoring the ballot.
Ms. Landrieu will have powerful partners this fall. Strategists at the Democratic Senatorial Campaign Committee are hiring field organizers for a $60 million effort in a dozen states to swell turnout among core Democratic groups such as African-Americans and single women.
The goal, said Matt Canter, the DSCC's deputy executive director, "is to make the electorate look more like it did in 2012 than it did in 2010." With the data-driven tools that helped power Mr. Obama's two presidential wins, he said, "we can alter the electorate."
In five states that could be the most critical to continued Democratic control of the Senate -- Arkansas, Georgia, Louisiana, Michigan and North Carolina -- party strategists believe there could be as many as 1.4 million unregistered African-American voters, and they have already begun to pursue them.
According to the latest figures from the Louisiana secretary of state, about 87 percent of African-Americans are registered to vote -- with a remarkable 95 percent of African-American women registered. Many of Louisiana's residents were displaced by Hurricane Katrina, but black voting strength has largely returned to pre-storm levels, and almost all those votes go to Democrats.
Yet turnout by black voters can drop as much as 5 percentage points in midterm races compared to presidential contests -- and such a shortfall this year could be devastating for Ms. Landrieu.
Under the state's unusual rules, a candidate must win more than 50 percent of the vote in November to avoid a runoff. Ms. Landrieu fell under that mark in her second Senate race in 2002, but in a move that may presage her strategy this time, she eventually won in part by increasing the number of African-American voters who showed up for the runoff.
Interviews with black voters here hint at her advantages and challenges this fall. Many still speak reverently about her father, Moon Landrieu, and his efforts to integrate City Hall as New Orleans mayor in the 1970s. Her brother Mitch handily won re-election as mayor in February with 64 percent of the vote in the majority African-American city, following an intense get-out-the-vote drive that could lay some of the groundwork for his sister in November.