Clarence Thomas has served as a Supreme Court Justice since 1991, when he was nominated by President George H. W. Bush. Upon his appointment, Thomas supplanted Antonin Scalia as the most conservative member of the high court.
Thomas's nomination sparked an incredible political controversy which was highlighted by a former colleague, Anita Hill, alleging him of sexual harrassment. An FBI document containing Hill's allegation was leaked during Thomas's confirmation hearings. The hearings went on to become one of the most bitterly contested in history, with special interests weighing heavily in the fight. In the end, the Senate decided there was not enough evidence to support Hill's allegations and approved Thomas by a vote of 52-48, the slimmest margin ever.
With a highly fundamental reading of the constitution and political beliefs centered around limited government, Thomas has a history of voting against the environment.
Even more, he has been implicated in claims of impropriety and conflicts of interest, most notably in regard to the landmark campaign finance case, Citizens United v. Federal Elections Commission. In 2010, the Supreme Court ruled in favor of Citizens United by a vote of 5-4. The decision overturned a century's worth of legal precedents, opening up the floodgates for corporate financing and advocacy in U.S. elections.
In 2008, after the Citizens United case had been brought to the Supreme Court, Clarence Thomas attended an exclusive "political strategy" retreat held by the Koch brothers. The Koch brothers have fed hundreds of millions of dollars into conservative advocacy groups and think tanks such as Citizens United. These retreats are attended by corporate CEOs, lobbyists, and advocacy groups. The attendees of the 2008 retreat, therefore, stood to gain an incredible amount of influence and leverage with the high court's decision on Citizens United v. FEC.
Through a spokesperson, Thomas claims only to have "dropped by" the retreat. Alternet reports, however, that in his financial disclosure reports for that year, Thomas claimed the Federalist Society, a prominent conservative legal group, reimbursed him an undisclosed amount for four days of travel, meals, and accommodations over that weekend.
Even more, Citizens United was one of the special interest groups which lobbied for Thomas during his fierce Supreme Court nomination battle
Common Causes, a government watchdog group, has a running petition to investigate the Citizens United case based on conflicts of interest.
Over the years, Thomas has been linked to other acts of impropriety including receiving a $15,000 gift from the American Enterprise Institute, a conservative think tank which has filed briefs before the Supreme Court. Harlan Crow, a leading conservative donor, has also given Thomas gifts, including providing $500,000 for Thomas's wife, Virginia, to start Liberty Consulting, a lobbying firm. Think Progress has put together a quick read of Thomas's questionable activities.
In 2011, Virginia Thomas earned income lobbying against Obamacare. Obama's health care reforms were taken to the Supreme Court. Clarence Thomas did not recuse himself from the case and voted against the reforms. Nevertheless, the Supreme Court upheld the health care act.
Finally, in 2011, Thomas refused to recuse himself in a Supreme Court case involving Monsanto. From 1977-1979, Thomas worked as a lawyer for Monsanto.