Facing a primary election last year, Representative Jesse Jackson Jr. was taking no chances. He gathered dozens of local pastors for a news conference here, where they prayed against “political demonic forces” and fiercely endorsed the 17-year congressman for another term.

“They’ve known my highest moments, and they’ve known my lowest moments,” Mr. Jackson said of the mostly African-American ministers who surrounded him. “And on some Saturdays and on every Sunday each one of these pastors prays for somebody just like me.”

It is not surprising that a crowded field of candidates is courting the same kind of clergy support in a Feb. 26 special primary election to replace Mr. Jackson, who resigned his Second Congressional District seat 15 days after winning re-election in November. Now facing a short campaign sprint, those candidates say the backing of ministers and invitations to stump at multiple church services each weekend remain the sacraments of any good election ground game in the district, which includes parts of Chicago’s South Side and southern suburbs.
Like in many districts across the country where African-Americans are the majority, the Second District has counted black ministers among the most influential voices for decades. Their endorsements, trusted by many churchgoers, are traditionally seen as an indication of how those congregants may vote on Election Day.
“We want it to stay an African-American seat,” said Carl L. White Jr., the pastor of Victory Christian Assembly in Markham, Ill., and the president of the Southland Ministerial Health Network. “We want a voice for us in this area. There’s access that comes with culture."