Referring to “ex post facto, or double jeopardy, protections,” The Post conflated separate aspects of criminal law [“Ruling could shake up Md. sex- offender registry,” front page, June 22]. An ex post facto law retroactively criminalizes conduct that wasn’t a crime before the law was passed or increases the penalty for a crime after it was committed. Double jeopardy is being tried twice for the same crime.

Hank Wallace, Washington