Adds a rule to federal pretrial detention law that lets a judicial officer treat certain defendants as a danger to the community and deny release before trial if three things are true: the person is charged with a federal felony, is an adult (or a juvenile charged as an adult), and has a prior violent felony conviction for which they served at least 30 days in state or federal prison (time in pretrial detention does not count). The change narrows eligibility for pretrial release for defendants with specified prior violent-felony convictions.