Peterson's lawyers have asked a judge to declare the law unconstitutional.
The attorney general is responsible for defending the constitutionality of state laws.
AG Madigan to weigh in on Peterson case
August 18, 2009 At issue is a new Illinois statute that allows some "hearsay" evidence to be used in court.
In Drew's case prosecutors would be able to use incriminating statements his third wife, Kathleen Savio, made before she was found dead, or his fourth wife Stacy Peterson, made before she disappeared.
