Is Military Newspaper a Nonpublic Forum?

Today, in Bryant v. Gates, the U.S. Court of Appeals for the D.C. Circuit held that the advertising section of the Defense Department's Civilian Enterprise Newspapers constitutes a nonpublic forum, and upheld the Department's ban on "political" advertisements.

Of particular interest may be Judge Kavanaugh's concurring opinion, in which he suggests the government could (and should) have defended its policy on the grounds that the newspapers constitute government speech, rather than a nonpublic forum, and cites our own Eugene Volokh in the process.