Deterrence exists, but all the research (in the US) suggests it&#x27;s caused by certainty of punishment, not magnitude of punishment. A two-week stint in jail that&#x27;s almost guaranteed will do far more to deter criminals than a ten-year stint that almost never happens.<p>Unfortunately, it&#x27;s much easier to crank up the penalties and posture as &quot;tough on crime&quot; than it is to make sure police are actually closing cases.