In the case of Mattiello v. Connecticut in 1968, the U.S Supreme Court upheld a decision by the Supreme Court of Errors of Connecticut which found State Senator Anthony V. Mattiello guilty on charges related to corruption and conflict of interest. The charges stemmed from his involvement with an insurance company while serving as chairman for a legislative committee overseeing insurance matters in Connecticut. He was accused of using his position to influence legislation that would benefit him financially through this connection with said insurance company. Mattiello appealed to the U.S Supreme Court arguing that he had been denied due process because some members who sat on his trial were also part of an investigatory committee looking into allegations against him earlier, thus creating biasness or prejudgment about his guilt or innocence before trial began. The court rejected this argument stating there was no constitutional requirement barring those who have participated in investigative stages from sitting at subsequent trials unless there is proof they are biased against defendant's case; something which Mattiello failed to demonstrate convincingly.

In the dissenting opinion for Mattiello v. Connecticut, it was argued that the majority's decision to uphold a state law prohibiting picketing near schools violated First Amendment rights. The dissenting justices believed that peaceful picketing is a form of expression protected by the Constitution and should not be restricted unless there is clear evidence of imminent danger or disruption to school activities. They also disagreed with the majority's view that children are more susceptible to emotional disturbance from such protests, arguing instead that students could benefit from exposure to different viewpoints and public debate on important issues. Furthermore, they expressed concern about giving states too much power in regulating speech around schools which could lead to further restrictions on free speech in other areas.