A Chicago Mercantile Exchange trader and three other people have joined with the Illinois Association of Firearms Retailers to sue the city of Chicago over a restrictive gun law passed by its legislators last week. The gun-owning plaintiffs, who include a teacher's aide and a married couple, claim the new ordinance restricting handgun possession to inside the home and mandating firearms training and permitting is unconstitutional. The measure imposes "new restrictions... (GunPolicy.org)