Strategic Deterrence is the policy used by the United States to dissuade adversaries from launching a nuclear attack. This is made up of three different segments – or legs: Land-based intercontinental ballistic missile, strategic bombers, and nuclear-powered ballistic missile submarines. To truly have a credible deterrence policy the nation must have a means of protecting at least some of its missiles from a first strike from an aggressor. The most survivable leg is the submarine. These submarines go on patrol and are hidden at sea for months at a time waiting for a call they hope will never come. Here we look at the submarine force contribution to strategic deterrence – starting before the ballistic missile with the Regulus, continuing on through the first ballistic missile system – Polaris A-1, and ending with the current Trident missile system.