DOJ says it's not found PATRIOT Act abuses when it investigates itself
I'm not an expert in the PATRIOT Act but assuming there are parts of the Act which are obnoxious to the Constitution it would be really dumb to use those powers generally. At least in the beginning you would use them sparingly, in the most extreme cases where it would be very difficult for an appellate court to overturn the conviction. After all, how often do you read statements like this in an appellate court decision? "Despite the fact that the defendants killed six police men in the bank robbery which was done to support Hamas activities, we find that the evidence must be thrown out as fruit of the poisonous tree because it all stems from a violation of the constitution under section ____ of the USC as amended by the PATRIOT Act."
Thereafter you would expand the power to more common cases where attempts to curtail it would be difficult because of the established case law.