Begala penned an email the day before the fundraising quarter ends comparing Nunn to the last Democrat to carry Georgia, President Clinton.
"I get that same feeling when I look at Michelle Nunn's candidacy for Senate. Since it's not my first rodeo, I am not prone to irrational exuberance. But Michelle is the real deal. She is an outstanding candidate with a real chance to win in Georgia. She would make history as the first woman Georgia has ever elected to the Senate."
Begala calls Nunn, a former charity executive who's running as a centrist, "a powerful, pragmatic practitioner of the politics of common ground."
Nunn's campaign is off to a strong start in the Republican-leaning state. She hauled in $1.7 million in her first quarter in the race, the largest sum of any non-incumbent Senate candidate.
Her campaign has the backing of some other former Clinton hands as well. Gordon Giffin, Nunn's campaign chairman, was a top donor to both Bill and Hillary Clinton's campaigns and served as the ambassador to Canada during Clinton's final years in the White House.