Since his appointment to the Supreme Court, Justice Thomas has participated in several cases involving his previous employer—in none of these cases did he follow the judicial codes of conduct and recuse himself:
Monsanto Co. v. Geertson Seed Farms: In 2010, the Supreme Court decided a case that affected regulations on GMO “RoundUp Ready” alfalfa. The decision of this case was a 7-1 vote, in favor of Monsanto. Despite his obvious conflict of interest, Thomas did not recuse himself from this case. In contrast to Thomas, Justice Breyer recused himself from the Monsanto v. Geertson Seed Farms case because his brother, Charles Breyer, was the Federal judge whose decision was being appealed.
Bowman v. Monsanto Co.: In 2013, the Supreme Court decided a case which expanded the patent rights of GMO manufacturers to include naturally reproduced seed stock—this would prevent farmers from saving and naturally replicating Monsanto seeds as they would do with spare non-GMO seeds. While this decision was unanimous and Thomas’s vote was ultimately irrelevant, the fact that he refused to recuse himself in a case of such import involving his former employer is indicative of his pattern of disregarding conflicts of interest.
While there is no direct evidence supporting any continuing financial entanglements between Justice Thomas and Monsanto, there are several indirect connections which further increase the conflict when Thomas decides a case involving Monsanto (these connections are interesting but unnecessary, as the simple fact that he worked there is enough of a conflict to necessitate recusal).
Over the past few years, Justice Thomas has taken numerous expensive gifts and social engagements from groups which are extremely pro-agribusiness. In particular, Thomas’s acceptance of a $15,000 “gift” from the American Enterprise Institute and his speaking engagements in front of the Federalist Society present a conflict in regard to his deciding GMO cases. Both AEI and the Federalist Society consider themselves conservative “free-market” think-tanks, and have been virulently against increased regulations on GMO producers. As such, Thomas’s involvement with these groups creates a pressure for him to rule in favor of corporate interests—after all, if he were to vote against GMO producers, it is likely that he would no longer receive the money of AEI or the prestige of speaking in front of the Federalist Society.
https://theprogressivecynic.com/2013/07/15/justice-clarence-thomas-and-monsanto/