It is, yes. The specific mechanism is that most cases don't go to trial; accused are offered plea deals with the threat that they will receive a much, much harsher sentence if they push for a trial. This threat is often made good too: police testimony is usually enough to get a guilty verdict and police say what prosecutors want them to.

Basically if they want you they've got you. To get out you have to have a very specific alignment of resources, sympathy and luck, and the risk if it doesn't work out is massive even then.