(CNN) As a contingent of well-wishers flood the nation's capital to pay respects to George H.W. Bush, one of the former president's most lasting legacies took his seat Monday morning at the Supreme Court to hear arguments in a tax case.

It's been more than quarter century since Bush left the White House, but Justice Clarence Thomas — appointed by Bush in 1991 — serves as a reminder that a president's impact can reverberate long after his presidency. Thomas is hard at work trying to reshape the law and his former clerks now populate the Trump administration and the lower courts. Whether a president gets the opportunity to fill a Supreme Court vacancy is often left to chance or circumstance, but Bush got two chances, and he chose two very different judges.

Thomas took the seat of the civil rights legend Justice Thurgood Marshall. At the time, the nomination of the 43-year-old Thomas was a crushing blow to civil rights groups, which had hoped in vain that Bush might take the opportunity to fill the seat with someone closer to Marshall's judicial philosophy. Instead, Thomas, now the longest serving justice, is perhaps one of the most conservative members of the court, sometimes writing alone and hardly ever speaking during oral arguments, but laying a marker of conservative jurisprudence that will last for decades to come.

Thomas has emerged as a star of the conservative Federalist Society and frequently speaks before the group to standing ovations. "I've gotten to the point where it's like the priesthood. This is what I was called to do," Thomas told an audience in 2013.

His supporters were stunned when the Smithsonian opened a major museum in 2016 meant to promote and highlight the contributions of African Americans and almost entirely ignored the achievements of Thomas, who rose from poverty to serve as the country's second African-American associate justice of the Supreme Court. The museum did have a picture at the time of Anita Hill, who famously blew up Thomas' confirmation hearings with allegations of sexual harassment. Thomas — who always vehemently denied Hill's accusations — never addressed the Smithsonian controversy publicly.

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