Orin Kerr over at the Volokh Conspiracy takes a negative view of briefs filed at the Supreme Court by legislators:
Amicus briefs written on behalf of sitting legislators strike me as inappropriate. Of course, legislators can influence the judicial process in many ways. They write the legislation that the courts interpret; they control the rules that govern judicial hearings; they can control much of the Courtâ€™s docket; and they even control how many Justices are on the Supreme Court. Further, legislators take an oath to uphold the Constitution, and they have an independent (albeit sporadically exercised) duty to ensure that legislation they enact passes constitutional muster.
From a theoretical point of view, I can understand where Professor Kerr is coming from here. But I am not a law professor. I’m a Second Amendment activist, and from my point of view, as long as the courts take an attitude of deference to the elected branches, I have no problems with the elected branches demonstrating for the Court that they have a preference for a certain outcome in a particular case or controversy, especially when such an important and key constitutional issue is at question, such as the case with McDonald. In an ideal world, the Supreme Court would decide cases based solely on what the law and constitution says, and the elected branches would stay out. But we do not live in that ideal world.