What is the definition of "ex post facto" in relation to search and seizure?

The definition of "ex post facto" refers to a law that imposes legal consequences on actions that occurred before the law was enacted. In the context of search and seizure, the principle indicates that individuals cannot be penalized or have their rights infringed upon based on laws that were not in effect at the time of their actions. This means that if a search or seizure was conducted before a law was established, the law cannot retroactively apply to that situation in a way that would alter its legal ramifications. This protection is foundational in ensuring fair legal processes and preventing arbitrary punishments based on newly established regulations.

The other options focus on different aspects that do not accurately capture the essence of "ex post facto" as it pertains to search and seizure law. For example, laws changing consequences retroactively would contradict the fundamental purpose of the ex post facto rule, while policies allowing for retroactive searches do not align with the protections typically afforded under this principle. Additionally, the mention of border searches relates to different legal frameworks and exceptions that do not pertain to the definition of "ex post facto."