Criminal law is an area of law that is normally reserved to the states. The federal government pursues its own investigations in cases that are primarily interstate criminal operations and often work with the specific states in large investigations, but the federal government prosecution always reigns supreme in any criminal charge. If the federal government deems that a legal issue is solely a jurisdictional responsibility for the state, then the state case normally is allowed to proceed.
If an investigation is extensive across a significant number of state boundaries the charges are then filed in federal district court in the federal judicial offices nearest to the illegal activity. Federal charges are adjudicated by different sentencing and conviction guidelines and the dispensation of punishment is different in terms of probation and parole. Federal sentencing guidelines normally require at least some level of incarcerated punishment, but this is not always the case. In the event that the defendant has had convictions in the past, the eligibility for probation is significantly compromised. There are situations where judges can exercise judicial latitude when the threat to public safety is low. Rarely are cases totally dismissed.
The majority of all criminal convictions are delivered in state courts, primarily because no one lives “federally.” Though the perpetrators are in the United States, everyone has a local state residence also and the prosecuting police agency determines the court of jurisdiction by location of the criminal incident. There are some situations where actions in a state are deemed legal by state statute, but unlawful by federal law. The most common example of this occurrence is the medical marijuana movement across the nation. The Department of Justice is currently initiating a program of prosecuting medical marijuana dispensaries in states that have decriminalized marijuana possession based on medical need, claiming sovereignty over state statute by virtue of the federal contraband status of marijuana possession and sale.
Additionally, prosecution conflicts can occur when federal authorities enter into plea agreements with defendants that preclude any state prosecutions at the lower court level. This can be highly problematic for state judicial systems because these cases often include white-collar corporate crimes where the states would also have the standing to sue the defendant in civil court on behalf of victims in their states who were involved, often unbeknownst to the victim until it is too late.
A primary example of this situation is the current plea arrangement being sought in federal court by a number of banks under prosecution by the Securities Exchange Commission. The agreement being sought by the defendants and the SEC would suppress any consequent inferior state prosecutions and eliminate the civil tort standing of the actual victims of the crime. Federal law is sovereign to state law because of state incorporation to the non-governmental guarantees provided in the U. S. Constitution.