I can't vouch for the accuracy of this report (was a quick google search; PATRIOT was passed at a point in time where not everything was quite so webbified), but I recall the lawmakers who crafted PATRIOT used RICO as a starting point ("precedence") for the most controversial provisions. There are surely more authoritative resources out there.
"Some of the more controversial provisions of The Patriot Act were largely inspired by the RICO act, which restricted some elements of due process for individuals involved in organized crime, racketeering, and drug trafficking. The Patriot Act essentially extended the restrictions to those involved in terrorism."
http://www.johnisaza.com/patriot_act_compliance.html
"Some of the more controversial provisions of The Patriot Act were largely inspired by the RICO act, which restricted some elements of due process for individuals involved in organized crime, racketeering, and drug trafficking. The Patriot Act essentially extended the restrictions to those involved in terrorism."