What is the difference between a federal and a state case?

We are used to hearing the saying "don´t make a federal case out of it". Most individuals believe that federal cases are more serious than state cases. This is not necessarily true.The majority of cases are prosecuted by the State. This includes murders, rapes, and many other serious crimes. The federal government becomes involved in a case when one of their laws is broken. The federal government coins money and is responsible for the international and state borders. Therefore, most of the federal crimes involve illegally crossing drugs across borders, alien smuggling, unlawful entry into the United States and financial related crimes. The feds also may prosecute someone for committing crimes through the mail and the unlawful interstate use of telephones, for example telemarketing fraud.There are serious crimes at both the state and federal level.