State Sen. Vincent Fort, the No. 2 Democrat in the Georgia Senate, flipped his endorsement on Tuesday from Hillary Clinton to Bernie Sanders. He instantly becomes one of the Vermont senator's top surrogates in the South, where his campaign has picked up support from only a handful of black elected officials.

The Atlanta Democrat made his decision public just hours before Sanders was set to speak at a Morehouse College rally aimed at enticing black voters to give his campaign a second look. Fort, who is also considering a run for Atlanta mayor, had endorsed Clinton weeks ago.

"After months of looking at Bernie's record and studying his positions on healthcare, Wall Street, predatory lending and the minimum wage, I came to the conclusion that Bernie's position on the issues that affect my constituents in Georgia the most conform most closely to my positions," Fort said.

Sanders lost to Clinton in Iowa by a razor-thin margin before notching a 22-point victory in New Hampshire. But he faces a tougher challenge in the South, where polls show Clinton with an advantage over black voters in South Carolina, which votes on Feb. 27, and Georgia and other Southern states that follow on March 1.

It puts Fort at loggerheads with Georgia's Democratic establishment, which has overwhelmingly endorsed Clinton's campaign. Her top endorsements in Georgia include two of Fort's biggest rivals: House Minority Leader Stacey Abrams and Atlanta Mayor Kasim Reed.

(Reed said Tuesday it's "nothing but a publicity stunt to help him run for mayor. He will lose that race also.")

And it makes him the most high-profile Sanders supporter in Georgia. His other backers in Georgia include state Rep. LaDawn Jones and Clarkston Mayor Ted Terry.

Fort said Sanders' call for income equality and his attacks on a Washington establishment that favors the rich over the poor will resonate in the region as more voters tune in.

"He's going to do well here. As people have a chance to listen to him, to have a chance to understand that he's speaking to the issues that are the most critical," said Fort. "As people study and listen to him, I think there's going to be movement toward his campaign."