TCF Financial Corp. CEO Bill Cooper spent much of his political career and personal fortune helping Republican candidates and pounding on Democrats.

A former chairman of the Minnesota Republican Party, Cooper has accused Democrats over the years of being "soft on crime," wrong on the economy and wrong on the budget.

So some were surprised by the attorney TCF selected to represent it in a federal lawsuit against several property-appraisal companies: Brian Melendez, a former DFL Party chair.

"Given the stridency of Bill Cooper in the political arena, it is amusing," said Chris Georgacas, another former state GOP chairman. "It will bring a smirk to a lot of people's faces."

Others say the pairing just proves that enemies in one arena can become fierce allies in another. Money, they say, is not entirely partisan.

"That is funny," said Tony Sutton, former Minnesota GOP chairman. For several years, Sutton and Cooper were partners in Baja Sol, a fast-casual Mexican restaurant chain.

"I guess, well, Brian is a competent lawyer," Sutton said. "It shows you there are things above politics."

Melendez did not exhibit the same sense of humor about the situation.

"It's a big law firm," he said. Melendez is a partner in the Minneapolis office of Faegre Baker Daniels, which focuses on business litigation and consumer finance.

Melendez noted he does not report to Cooper -- far from it, in fact.

"I deal with people who report to people, who report to people who report to him," Melendez said. "Mr. Cooper is several pay grades above the people I report to."

Does he see how people could think it is funny he is working for someone who was once bent on destroying the DFL? "Sure, I guess I do," Melendez said.

He did note that he and Cooper never served as party chairs at the same time. Cooper was GOP chairman from 1997 to 1999; Melendez ran the DFL for six years, stepping down in 2010.

Melendez said he met Cooper for the first time two years ago. Now, he said, he is squarely focused on law, not politics.

"I enjoy my day job," Melendez said. "I am not dealing with any politics, and that's just fine."

Cooper said he holds Melendez "in high esteem, and I consider him a very honorable attorney."

He also keeps politics and business separate.

"I don't make those connections at all in the business world," he said. "People have the right to their opinions."

Cooper did say he was impressed with how Melendez ran the DFL.

"He did a great job running the party," Cooper said. "He was probably the best party chair they ever had. He's very smart and got things organized."

Despite their past political roles, Cooper and Melendez are not entirely uncompromising partisans.

While Cooper has given hundreds of thousands of dollars to GOP causes and candidates, he has given money to Democratic candidates like U.S. Sen. Amy Klobuchar.

Melendez, for his part, co-hosts an annual nonpartisan holiday party.