Which 1991 Metallica album song was issued to rock radio but not as a commercial single?

“Don't Tread on Me” was issued to rock radio but not released as a commercial single from Metallica's 1991 album Metallica.

The song appears as the sixth track on the standard album. Its title refers to the Gadsden flag and the phrase “Don't Tread on Me,” a historic American political motto. The lyrics use that imagery in a song about strength, independence and deterrence.

Metallica promoted five commercial singles from the album: “Enter Sandman,” “The Unforgiven,” “Nothing Else Matters,” “Wherever I May Roam” and “Sad but True.” “Don't Tread on Me” received rock-radio promotion, but it was not issued as a commercial single in the same way as those five songs.

That distinction can cause confusion because radio promotion and commercial single release are separate parts of an album campaign. A song may receive airplay without being sold as a standalone single. The track was still important to the album's identity and later received a gold certification from the RIAA as part of the album's enormous sales success.