When can a defendant waive their right to a jury trial?

A defendant can waive their right to a jury trial during their arraignment. At this stage of the legal process, the defendant is formally presented with the charges against them and given an opportunity to enter a plea. It is also at this point that defendants can make critical decisions about their trial rights, including whether they wish to proceed with a jury trial or opt for a bench trial, where a judge makes the final decision.

Choosing to waive the right to a jury trial in this context shows that the defendant has acknowledged their options and made an informed choice regarding how they prefer to handle their case. The arraignment serves as a pivotal moment when a defendant can exercise their rights in a structured legal manner. In contrast, the other situations mentioned do not provide the same level of opportunity or formal recognition of the defendant's choices regarding trial methods. For example, being arrested does not involve making this decision, and preliminary hearings or grand jury proceedings focus more on establishing probable cause rather than the plea or trial options available.