Copyright is confusing. Most people understand “public” or government produced material, like statutes, regulations, and court opinions, is not protected by copyright. And generally that’s true regarding the actual statute, regulation, or court opinion but a state or even local entity may be able to protect the arrangement, numbering, or annotation of these materials.
Katie Fortney in Ending Copyright Claims in State Primary Legal Materials, 102 Law Libr. J. 59 (2010), has done a nice job laying out some of the arguments and presenting a few suggestions of her own regarding broad free access.