The case In re John Robert Demos, Jr. (1990) involved an attorney who was disbarred from practicing law in the state of New York due to professional misconduct. The Supreme Court of the United States upheld this decision after reviewing his appeal. The charges against Demos included neglecting legal matters entrusted to him, failing to return unearned fees, and not cooperating with investigations into his conduct by disciplinary authorities. He also failed to notify clients about his suspension from practice and continued representing them unlawfully during that period. His actions were deemed as a violation of ethical standards set for attorneys which led to severe consequences such as disbarment.

The dissenting opinion in the case of In re John Robert Demos, Jr., 1990 argued that the majority's decision to deny Mr. Demos' petition for a writ of habeas corpus was incorrect and unjust. The dissent believed that there were significant issues with how his original trial was conducted, including ineffective assistance from his counsel and prosecutorial misconduct during closing arguments. They also disagreed with the majority's interpretation of certain legal standards related to these claims, arguing they had been applied too stringently against Mr. Demos. Furthermore, they expressed concern about potential racial bias influencing jury selection in this case due to Mr. Demos being African American and suggested it may have violated his constitutional rights under Batson v Kentucky (1986). Overall, the dissent felt strongly that these cumulative errors could have significantly impacted the fairness of Mr.Demos' trial and thus warranted further review by federal courts through granting him habeas relief.