Lewis, one of the most influential House Democrats, was among dozens of lawmakers who flipped their position last week to support impeachment proceedings after new details about Trump's discussions with Ukraine's leader emerged.

Ossoff, one of four Democrats challenging Perdue, has taken a different stance. He said he supports impeachment if allegations prove true that Trump “pressured a foreign power to smear his political opponent, dangling security assistance as leverage.”

Much of the rally focused on rolling out what Ossoff has promised will be the largest statewide voter registration drive in state history when taken together with other partisan efforts and Stacey Abrams’ initiatives. He said his campaign and others should build on the work from Abrams and the New Georgia Project, a voter registration effort she helped launch.

He also said his campaign’s attorneys were ready to bring lawsuits or join legal challenges to contest potential voting rights violations.

“The rolls have been purged. Names have been stricken and denied,” said Ossoff, who earned national attention in 2017 with his unsuccessful run for Georgia’s 6th Congressional District.

Jon Ossoff , Democratic candidate for one of Georgia's U.S. Senate seats, signs autographs during a voter registration rally at the MLK Recreation Center in Atlanta on Saturday, September 28, 2019. (Photo: STEVE SCHAEFER / SPECIAL TO THE AJC) Credit: Steve Schaefer Credit: Steve Schaefer

“You’ve been asked to wait six hours to cast your ballot. Jim Crow lives in the South today, but we can put a stop to it. We have the power to put a stop to it. We cannot give up. Did Congressman John Lewis give up?”

The event, close to the King Center, served as a reminder of Ossoff's efforts to align himself with prominent black leaders. All four Democrats in the contest against Perdue are white, unnerving some party activists and strategists who worry about energizing the party's liberal base next year.

The three other Democrats who have their eye on Perdue's Senate seat: Former Columbus Mayor Teresa Tomlinson, Clarkston Mayor Ted Terry and business executive Sarah Riggs Amico.

Lewis, whom Ossoff considers a mentor after he interned for him, pledged his support for the 32-year-old throughout the campaign.

“I’m prepared to travel with you and visit all 159 counties with you,” Lewis said to cheers.

U.S. Rep. John Lewis talks to the crowd as Senate candidate Jon Ossoff looks on during a voter registration rally at the MLK Recreation Center in Atlanta on Saturday, September 28, 2019. (Photo: STEVE SCHAEFER / SPECIAL TO THE AJC) Credit: Steve Schaefer Credit: Steve Schaefer

And Ossoff also introduced an influential new supporter: State Rep. Karen Bennett, who chairs the state’s Legislative Black Caucus. After she echoed demands for national Democrats to invest more in Georgia – “now is the time, not tomorrow, not next year,” she said – she offered a pledge to Ossoff.

“We are behind you and we will do what we can to bring home this office for Jon Ossoff as the next United States senator,” she said.

Georgia's other Senate seat also has the attention of Democrats after three-term Republican Johnny Isakson announced recently that he would step down at year's end because of medical issues. Gov. Brian Kemp will appoint someone to fill the remainder of Isakson's term ahead of the seat being up for grabs in next year's election.