Final answer:
The first televised presidential debate was between John F. Kennedy and Richard Nixon in 1960, which had a significant impact on the public's opinion and highlighted the importance of media presence in politics. The first televised murder trial was not provided in the excerpts, and the O.J. Simpson trial is often cited as a notable televised court case, but it was not the first.
Step-by-step explanation:
The murder trial that marked the first time television cameras were allowed into the courtroom was not explicitly mentioned in your provided excerpts. However, one of the early pivotal moments in the intersection of television and the American justice system occurred during the 1954 Army-McCarthy hearings. These hearings were not a murder trial but were significant as they were one of the first times Americans could watch a major political hearing on television. As for murder trials, the O.J. Simpson trial in the 1990s is often remembered as a landmark case for televised court proceedings, drawing massive national attention, although it was not the first.
In terms of televised debates, the first ever televised presidential debate was indeed between John F. Kennedy and Richard Nixon on September 26, 1960. This debate is considered a defining moment in political history, notably influencing public opinion based on the candidates' television presence. It's mentioned that radio listeners thought Nixon had won, while television viewers favored Kennedy, signifying the impact of television on public perception.