On June 8, 1967, during the Six-Day War, the Israeli military attacked the USS Liberty, an American spy ship which had been monitoring Israeli transmissions about the conflict. Intercepted Israeli communications indicated that the goal was to sink the Liberty and leave no survivors.

Warplanes and torpedo boats had already killed 34 and wounded 174, when Halbardier slid over the Liberty's napalm-glazed deck to jury-rig an antenna and get an SOS off to the Sixth Fleet. The Israelis intercepted the SOS and broke off the attack immediately. In effect, Halbardier prevented the massacre of all 294 onboard. Still, the infamy of the attack on the Liberty was twofold.