Why? The effort comes after a week in which the long relationship between African American voters and the Clintons needed some reinforcement.
"This is a historic day," Rep. Charles B. Rangel (D-N.Y.) said as he introduced Bill Clinton at Antioch Baptist Church in Harlem on Sunday morning. "What makes it so important is that we have a chance to thank the Clinton family."
It was a reminder that perhaps seemed necessary after last week, when a group of Black Lives Matter protesters once again raised an old and thorny issue that has dogged the Clintons in this campaign: their support for a 1994 crime bill. The protesters took issue with then-first lady Hillary Clinton's use of the term "super predators," which critics now see as coded racial language targeted primarily at black urban youth who had been caught up in drugs and violence.
Fast-forward about 20 years, and Hillary Clinton has expressed regret for using the term, but Bill Clinton last week defended the crime bill and objected to protesters criticizing his wife for using a term that at the time targeted drug dealers and killers.
The episode launched a thousand reprises of the debate over whether the Clintons were truly contrite about the unintended consequences of the crime bill, which some blame for codifying a culture of mass incarceration that has decimated African American families.
So the former president made his pilgrimage to three black churches, pillars of the black community in Harlem, on Sunday morning.
Rangel reminded the congregation that Hillary Clinton pressed her husband during his presidency to include Harlem as an economic empowerment zone so it could receive economic development funding. And that Bill Clinton, after finishing his presidency, chose the neighborhood to house his presidential foundation's office.
But Bill Clinton was also in Harlem to express a little more contrition that seemed to be lacking in his fiery defense of the crime bill in Philadelphia last week.
"Not all our problems are economic. We need police reform. ... One of the things Charlie Rangel helped me to get was more police on the street who looked like the people they police," Clinton told the congregation at Abyssinian Baptist Church. "We need prison reform. We overdid it and put too many young, nonviolent offenders in jail for too long."
Across town, Hillary Clinton also spent the morning -- as she often does -- in black churches in New York City. She defended President Obama's legacy and recounted how he asked her to serve in his administration.
She also addressed criminal justice reform.
“We need to end the era of mass incarceration and make sure we divert people from going into prison in the first place" and help people coming out of prison as well, Clinton said at New Greater Bethel Ministries in Queens.
For Clinton, the timing of these church visits happened to be just right, but black churches are like a second home to the former first family. The Clintons are regularly greeted with a hero's welcome in them, and they have become regular guests over the years. ("This is a woman that I have faith in. … This is not her first time in this place," said the Rev. Floyd Flake of Greater Allen AME Cathedral of New York in Queens.)
Speaking to a spirited audience in Baltimore later in the day, Clinton accepted the endorsement of Rep. Elijah E. Cummings (D-Md.) and emphasized her proposals to boost economic development in predominantly African American communities in Baltimore and elsewhere.
On Sunday alone, the Clintons were backed by Rangel, Rep. Gregory W. Meeks (D-N.Y.) and, later, by Cummings -- all of them black lawmakers and community leaders who have regularly helped both Clintons among black voters nationwide.
"One of the things that meant so much to me, Madam Secretary, is one of the first speeches that you made when you were about to launch your campaign to make sure that every single citizen has an unimpeded right to vote and have their vote counted," said Cummings, a native son of Baltimore. "So that's Hillary's road, the road that will lead our nation forward. The road that will bring us much closer to a more perfect union.
"I'm following that road, and I'm following it with Hillary Clinton," he added.
Later in the day, Clinton took time off of the trail to attend a fundraiser at the home of Va. Governor Terry McAuliffe, with entertainment by Carole King.