Former Sen. Richard Lugar, a Republican, has given the maximum amount of money allowed under federal campaign finance laws to a candidate who hopes to help Democrats retain the Senate in the 2014 election.

Michelle Nunn used the $5,000 donation to appeal to conservative Georgia voters. "I am immensely honored and grateful for Senator Lugar's generous support in this race," she said. "Both in the Senate and in the international community, Senator Lugar's collaborative approach made us safer and moved our country forward. We need more leaders like Senator Lugar -- not less, and I will strive to follow this legacy in the U.S. Senate."

The Lugar-backed 19th Star PAC gave Nunn $5,000, the most that a PAC can give an individual candidate, the Huffington Post reported.

After 36 years, Lugar lost his Senate seat from Indiana in 2010 when State Treasurer Richard Mourdock defeated him in the Republican primary by arguing that he was too moderate.

“When Dick Lugar moved to Washington, he left behind more than his house. He left behind his conservative Hoosier values,” one Mourdock ad against Lugar told voters. “Lugar's been in Washington 36 years. That's too long. Time for a change.”

Mourdock's general election campaign foundered after he said, “I think even when life begins in that horrible situation of rape, that's something God intended to happen” during a debate. The seat is now held by Democratic Sen. Joe Donnelly.