SG files opposition in gun in parks case
SCOTUSBlog has a link and discussion. The brief argues that (1) the regulation has been revoked by legislation, hence its constitutionality is not worth reviewing, and (2) the regulation could be justified under intermediate scrutiny.
UPDATE: I think he's referring to intermediate scrutiny, which is applied (as I recall) to most content-neutral time-place-manner restrictions on speech. I.e., you can't use a bullhorn at night in a residential area, and we don't care which side or what issue you speak on.