Criminal law is the foundation on which all elements of a criminal justice system rest. It determines what behavior is outlawed so that citizens are put on notice and so that police officers know when to make arrests. It sets different penalties for crimes so judges know how to punish offenders and the corrections department knows how long to incarcerate them. It is also layered: Each jurisdiction with a governing body can and typically does enact its own criminal laws. Congress creates federal laws, the Michigan Legislature enacts state-level crimes and local municipalities institute ordinances. This section will deal with state-level and municipal-level criminal law, describing the legislative process for enacting crimes and explaining the characteristics of crimes and civil infractions.
Sheria ya jinai ni msingi ambao vipengele vyote vya mfumo wa haki ya jinai vinategemea. Sheria hiyo inaweka sheria zinazopinga tabia za watu, ili kuwaonya raia na kuwaambia polisi wakati wa kukamata watu. Sheria hiyo inaweka adhabu tofauti kwa makosa ya uhalifu ili mahakimu wajue jinsi ya kuwaadhibu wahalifu na idara ya marekebisho ya kujua ni kwa muda gani wanapaswa kuwafunga gerezani. Pia ni layered: Kila mamlaka na mwili wa utawala inaweza na kwa kawaida hufanya kutekeleza sheria zake mwenyewe za jinai. Bunge huunda sheria za shirikisho, Bunge la Michigan hutekeleza uhalifu wa ngazi ya serikali na manispaa za mitaa huanzisha maagizo. Sehemu hii itashughulikia sheria ya jinai ya ngazi ya serikali na ya manispaa, ikielezea mchakato wa kisheria wa kuanzisha uhalifu na kuelezea sifa za uhalifu na makosa ya kiraia.