Gary Fields wrote an article for the Wall Street Journal on May 6, 2013 with the subtitle "Bipartisan Congressional Initiative Targets Bloated Federal Provisions Cited by Critics for Driving Up Incarceration Rates."
Key points of the article include:
"Federal lawmakers and legal experts attribute part of the continuing increase to the rist in criminal offenses and regulations that carry prison time and the creation of laws that don't require knowledge of wrongdoing."
"...the U.S. has weakened a long-standing legal principle known as mens rea, Latin for "a guilty mind," which means the person must know they are doing something wrong before they can be found guilty."
The entire article can be found here.