Perhaps he doesn't think America's declining economy has done enough to discourage undocumented immigration or perhaps he's disappointed that his vaunted employer sanctions law has thus far claimed zero victims, or perhaps it's just payback for the business community's backing of Kevin Gibbons in the LD18 Republican primary last fall.
Whatever his motivation may be, Pearce is now proposing to suspend the Bill of Rights, specifically the Fifth Amendment, in his never-ending jihad against immigrants in Arizona (and America).
From the AZ Republic -
...In the coming year, Pearce plans to ask the Legislature to revise the law so that prosecutors can have civil subpoena authority, a prospect that critics of the law said would be an unnecessary expansion of prosecutors' powers...
Under current law (as I understand it - any lawyers reading this are welcome to correct anything I misunderstand in a comment), prosecutors can get a criminal investigation subpoena for records, one that requires a little nicety like probable cause. Under Pearce's proposal, prosecutors would basically only need to say to a judge "We want to go fishing" to force businesspeople to give up their records and thus give evidence against themselves.
Just a reminder of the applicable clause of the Fifth Amendment -
"No person...shall be compelled in any criminal case to be a witness against himself..."
And while Pearce has a long history of disregard for the U.S. Constitution (particularly the parts that protect people that he doesn't like from government persecution), that same phrase is contained in Article 2, Section 10 of the Arizona Constitution.
He may want to disregard or even suspend that document, too, but that is the same document that authorizes the existence of the lege and defines its powers (Article Four).
He may find that suspending that particular document would put a crimp in his plans.