The president made it very clear in several statements that he was looking for someone who would bring diversity to the Supreme Court -- not just in terms of gender or ethnicity, but also in life experiences. He had criticized the court several times in particular for its decision in the Lilly Ledbetter pay discrimination case. The court had ruled that Ledbetter failed to file her discrimination claim within 180 days -- as required by law -- of when the discrimination occurred. Ledbetter did not know when she was first discriminated against because employees generally do not talk to each other about how much they get paid. She only discovered the discrimination later in her work experience.
The president's criticism of the court's decision seemed to be saying that he views some of the justices as out of touch with what actually happens in the workplace and in other situations. Yes, Congress imposed the filing deadline but Congress also said civil rights laws are to be interpreted broadly and applying the law strictly here made no sense to Mr. Obama and others because of the type of discrimination. Congress, he and others would think, did not intend to shut out those workers.
When he voted against the confirmations of Chief Justice Roberts and Justice Alito, he said, as a senator, that they had voted as lower court judges too often and consistently against the weak and the powerless. I'm sure he continues to view them and the court's conservative majority in this way when the law does not require them to do so.
His selection of Sotomayor also, I think, reflects his view that the long dominance of white males on the court does not represent America and does not represent past presidents' best efforts to find the best and brightest nominees in all corners of our country.