DFL state Rep. Ryan Winkler came under withering criticism Tuesday for describing the U.S. Supreme Court's only black member as "Uncle Thomas."

Winkler, of Golden Valley, fired off an angry tweet after the high court's 5-4 decision to void a key portion of the Voting Rights Act: "VRA majority is four accomplices to race discrimination and one Uncle Thomas."

Challenged by angry conservatives on Twitter, Winkler, a Harvard-educated attorney who has served four terms in the Legislature, initially claimed that he didn't realize "Uncle Tom" was considered a racial slur.

"I didn't think it was offensive to suggest that Justice Thomas should be even more concerned about racial discrimination than colleagues." Winkler tweeted at one point. "But if such a suggestion is offensive, I apologize."

Later, he tweeted: "Deleted tweet causing offense regarding Justice Thomas. I apologize for it, but believe VRA decision does abet racism."

Winkler, who had been considering a bid for secretary of state, has called off his plans. He said it was a decision he made before "Uncle Thomas" started trending on Twitter and making headlines around the country, although not one he had voiced publicly.

"I intended to point out the fact that Justice Thomas had turned his back on African-American civil rights. I did not intend it as a racially derogatory term and I probably reacted too hastily in using a word that is very loaded," Winkler said.

He said that he thought of the phrase as meaning turncoat. The phrase actually refers to the title character in Harriet Beecher Stowe's 1852 abolitionist novel "Uncle Tom's Cabin." It has been used as an insult for at least a century, most often to describe African-Americans deemed too subservient to white authority figures.

"I guess my judgment is way off," Winkler said.

Asked if he believes his use of the term on social media will hurt his future political career, he said: "I don't know. I hope people judge people on the merits of what they do in public office and not on the firestorm of a term that is used hastily but with no malintent."

Winkler soon learned just how offensive the term is to some — including Democratic colleagues.

"I thought it was unfortunate," said Deputy Senate Majority Leader Jeff Hayden, an African-American DFLer from Minneapolis who earlier had served in the House with Winkler. "I talked to Ryan today and told him as much. I thought it was a poor choice of words and frankly, as leaders and public officials we have to be very careful about what we say. It most certainly comes off as prejudiced and biased and insensitive." Hayden said he still considers Winkler a friend and a good lawmaker.

Republican Party official Chris Fields condemned Winkler's remarks "as the secretary of the Minnesota Republican Party, as a black man, as a Minnesotan [and] as a concerned citizen who wants to see good professional discourse in Minnesota politics. … It's offensive, it's highly charged and it has no place in Minnesota politics," said Fields, who lost a congressional race last year to Democratic U.S. Rep. Keith Ellison.

Winkler's tweet was quickly picked up by national news outlets. "Democratic Lawmaker Did Not Realize It Would Be Offensive to Call Clarence Thomas 'Uncle Thomas,' " read the headline on New York Magazine's blog. By 5 p.m. Tuesday, the item had already become part of Winkler's short Wikipedia biography.

Jennifer Brooks • 651-925-5049