Well, check out his bio: Among other distinctions, Justice Thomas served as chairman of the Equal Employment Opportunity Commission from 1982 until 1990, when he was nominated to the DC Circuit by President George HW Bush. He was nominated to the Supreme Court in 1991.
Yet according to Barack, Justice Thomas wasn't prepared to serve as one of nine justices despite working for Senator Danforth, as an attorney at Monsanto, and in federal service for nine years as the head of a federal agency (a federal government tenure three times as long as Obama's). Yet we're to believe that Barack considers himself prepared to serve as the one and only President and leader of the free world after three paltry years in the US Senate (along with part time service in the state legislature)?
Wow. That's hubris.