What is the primary role of a grand jury in the U.S. legal system?

The primary role of a grand jury in the U.S. legal system is to determine whether there is enough evidence to justify bringing formal charges against an individual, which often leads to a trial. This process involves reviewing evidence presented by a prosecutor to assess whether probable cause exists for a criminal proceeding. The grand jury does not decide guilt or innocence; rather, it evaluates whether the accusations warrant further action in the judicial process, which is a crucial function in protecting individuals from unwarranted prosecution.

The other options describe different functions that do not align with the purposes of a grand jury. Grand juries do not conduct trials or hear appeals—those responsibilities fall to trial juries and appellate courts, respectively. Additionally, grand juries are not involved in sentencing; that role is exclusively reserved for trial juries or judges in the judicial system once a conviction has been reached. Understanding the specific function of the grand jury helps clarify its place in the broader legal framework, ensuring that the rights of individuals are upheld during the initial stages of criminal proceedings.