[2][clarification needed] After post-shakedown repairs and modification in November and December 1964, James Madison departed on her first deterrent patrol on 17 January 1965.

The incident occurred when the James Madison was departing Holy Loch in Argyll, Scotland, to take up station and collided with a Soviet submarine waiting outside the port to trail it.

Eric Graham, a marine historian from the University of Edinburgh, told BBC Scotland it could have been a diplomatic incident but because it was so deep into the UK home water it was an "embarrassment" that they wanted to keep quiet.

[2] Poseidon was replaced by Trident C-4 missiles during a comprehensive overhaul that took place at the Newport News (VA) Shipyard in the early 1980s.

She was decommissioned on 20 November 1992 and struck from the Naval Vessel Register the same day, and her inactivation at Mare Island was completed on 8 December 1992.