Under which circumstance does the 5th Amendment protect against self-incrimination?

The 5th Amendment provides protection against self-incrimination primarily during custodial interrogations. This is when an individual is in custody and being subjected to questioning by law enforcement agents. The rationale for this protection is rooted in the idea that, when a person is in custody, they may not feel free to leave and may therefore be more susceptible to pressure and coercion from authorities. This environment can compromise the individual's ability to make voluntary and informed choices about whether to answer questions, thereby necessitating the constitutional safeguards provided by the 5th Amendment.

In contrast, public questioning, non-custodial conversations, and discussions with friends do not offer the same level of protection. In these scenarios, individuals typically have more control over their situation and the ability to refuse to answer questions without the kind of coercive environment that custodial interrogations create. Thus, the 5th Amendment's protections are specifically designed to address the risks associated with being interrogated by law enforcement in a custodial setting, ensuring that individuals are not compelled to provide self-incriminating information under duress.