A Nebula-class starship whose captain, Benjamin Maxwell, waged an unauthorized private war against Cardassia in 2367.
The USS Phoenix was a Nebula-class starship commanded in 2367 by Captain Benjamin Maxwell, a decorated veteran of the Federation-Cardassian War who had lost his family to a Cardassian attack during the conflict.
After the war ended, Maxwell became convinced that the Cardassians were secretly rearming. Acting without orders, he took the Phoenix into Cardassian space and destroyed a science station, then a warship and a freighter, killing hundreds. Starfleet ordered the Enterprise-D to find him, with Cardassian observers aboard.
When Picard caught up with the Phoenix, Maxwell refused to stand down until Miles O'Brien, who had served under him during the war, beamed over and talked him into surrendering. Picard took Maxwell into custody but warned the Cardassians that the Federation was aware of their activities.