My state allows people who have been charged with crimes, but not tried or convicted, to be released from jail on a "personal recognizance" bond. However, judges sometimes impose conditions on this release, like attending anger management classes or abstaining from alcohol. How can the judge impose these conditions when the person is still presumed innocent? 

A "personal recognizance bond," also known as "release OR" or being let out on their "own recognizance," basically means the judge has released the person without bail, based on a written promise that the person will return to court. A judge can impose conditions on this release for pretty much the same reason that he or she can put the defendant in jail in the first place -- though presumed innocent, the judge thinks there's enough evidence to raise serious suspicions that criminal activity was afoot. Put another way, if the police hadn't pulled together enough evidence to charge the person, then the judge would have thrown the case out right away.

At this point, the judge has a choice of sending that person to jail or imposing some other restrictions on his or her freedom -- before trial. As restrictions go, pretrial release with conditions is a lot better than sitting in jail, and the courts and defendants know it. (Judges also know they need to ease jail overcrowding, but that's another story.) Therefore, courts have ruled that having to take classes or meet other reasonable conditions while awaiting trial is not a violation of defendants' rights.

So, what other types of pretrial release restrictions might a defendant encounter? When a judge grants pretrial release, it's to ensure two things. First, that the defendant realizes that freedom from custody doesn't mean freedom to forget about upcoming court dates. So a condition of release might be that the defendant ask permission from the court before leaving the local area.

Second, the judge wants to ensure that the defendant won't get into trouble while out and about in society. So the judge might require a defendant charged with drug possession to attend Narcotics Anonymous meetings.

The more serious the pending charges, the more restrictive the conditions tend to be. A defendant who fails to comply with the conditions of release may find him or herself returned to jail -- or at the very least facing an angry judge (which is not a great strategic move). That's a pretty big incentive not to be tardy to or absent from a court date!