Various opponents have raised this issue in the long political career of Georgia's Republican U.S. Sen. Johnny Isakson. Now, it's Democrat Jim Barksdale's turn.

During taping Friday of the only televised debate ahead of the Nov. 8 election, Barksdale brought out a new line of attack involving Isakson's role in a racial discrimination lawsuit tied to his father. The Democratic challenger, who trails the incumbent by 15 points in our latest poll, tried to paint it as a sign Isakson had "much more in common (with Republican presidential nominee Donald Trump) than you want us to believe," a reference to a 1973 racial discrimination lawsuit brought by the U.S. Justice Department against Trump's company.

In this case, the incumbent’s father, Ed Isakson, started out fixing up houses in downtown Atlanta and ended up managing Northside Realty for its owner, J. Howard Chatham. Johnny Isakson later took a job managing Northside’s then-new Cobb County office after a stint as a reservist during the Vietnam War, rising to president of Northside Realty in 1979.

That year, the courts concluded that the company had discriminated against blacks and fixed commissions on housing sales under his father’s stewardship. Johnny Isakson was not linked, but as president he handled Northside’s defense in the price-fixing suit, recommending a no-contest plea. Northside and Ed Isakson were fined.

Isakson, who over the years has been lauded for his work across political and racial divides, responded angrily Friday about the line of attack, saying those problems did not happen under his leadership of the company. He also defended his father, whom he called “a great American businessman."

In our archives, we found stories from Isakson's failed 1990 bid for governor against Zell Miller that detailed the issue. We also found this 1990 comment from former Atlanta mayor and U.S. Ambassador Andrew Young, who backed Miller but made clear what he thought of attempts to link the issue with Isakson:

"While I'm supporting Zell Miller,  I wouldn't hesitate to say that Johnny Isakson has grown beyond whatever heritage of racism may have been a part of his family. And I don't think this issue should be a part of this election."