Washington ? The White House dispatched first lady Michelle Obama to defend Supreme Court nominee Sonia Sotomayor on Wednesday, as part of a broad offensive to humanize the judge coming as former GOP House Speaker Newt Gingrich backed off his harsh criticism of her as a racist.

Mrs. Obama told students at a high school graduation that Sotomayor is “more than ready” to be a justice and compared the judge’s life story of humble beginnings and high achievement to the paths taken by her husband and herself.

Sotomayor, who grew up in a New York City housing project and went on to Princeton and Yale universities, “says she still looks over her shoulder and wonders if she measures up,” Mrs. Obama said at Howard University, chiming in on Sotomayor’s behalf as her husband began a Mideast trip.

It was a subtle but pointed counter to Republicans who have cited Sotomayor’s speeches and writings about how her background affects her work as a judge to question whether she would let her personal biases interfere with her judicial decisions.

Hours earlier, Gingrich told supporters in a letter that he shouldn’t have called Sotomayor a racist, adding that the word had been “perhaps too strong and direct.” But he said the 2001 speech that prompted his remark, in which Sotomayor said she hoped the rulings of a “wise Latina” would be better than those of a white male without similar experiences, was still unacceptable.

Gingrich conceded that Sotomayor’s rulings have “shown more caution and moderation” than her speeches and writings, but he said the 2001 comments “reveal a betrayal of a fundamental principle of the American system — that everyone is equal before the law.”

Sotomayor, 54, would be the first Hispanic and the third woman to serve on the high court.

Gingrich’s comments and similar ones by radio host Rush Limbaugh — who on Wednesday said Sotomayor would bring “racism” and “bigotry” to the court — have enraged Sotomayor’s backers and caused problems for GOP figures who have been pushing to bring more diversity to the party.