SLBMs were, and remain, the most cost-effective and successfully rated means for nuclear deterrence. 1 As one-third of the U.S. triad of nuclear strategic forces, which included Air Force bombers and silo-launched intercontinental ballistic missiles, the submarine missiles had something the others lacked—stealth. Missile silo locations and air bases are easily located. Aircraft of the era were readily tracked with radar. Airborne nuclear forces, by the 1960s, were butting up against rapidly advancing air-defense technology with enhanced accuracy and efficiency. This drove costs down, increasing the number of anti-air assets. The need for a swift nuclear response also played a role. Despite airborne alerts, aircraft would take hours to launch their missiles, compared to SLBMs, which are less than an hour from first notice to launch until target destruction. An additional factor was that the North Atlantic Treaty Organization (NATO) was already relying on U.S. nuclear forces in general for deterrence and for the implementation of NATO's own strategy. 2
The 1957 launch of Sputnik was a crucial turning point for the technological development of SLBMs. With the Soviet Union able to launch intercontinental ballistic missiles (ICBMs), no land- or air-based nuclear arsenals were safe from attack anywhere in the world. 3 The Strategic Air Command (SAC) was no longer invisible, nor were the United Kingdom's Royal Air Force (RAF) nuclear assets. Consequently, because NATO relied so heavily on SAC invulnerability, a new form of nuclear insurance and deterrence was needed—insurance that would not be as susceptible to destruction. 4 The United States recognized the extreme importance of the nuclear-powered ballistic missile submarine (SSBN) in providing deterrence and a platform for launching ballistic missiles, virtually without warning.
Missiles for Basing
Obtaining forward bases for American SSBNs was crucial to maintaining deterrent patrols to counter Soviet aggression. The United States agreed to sell 100 Skybolt air-launched ballistic missiles to the United Kingdom in return for the use of Holy Loch, Scotland, for Polaris submarine tenders and port facilities. 5 While the sale pacified British political demands for a nuclear deterrent, the deal gave the United States an incalculable military advantage in maintaining its own forces for operation against the Soviet Union.
The limited ranges of the early Polaris missiles (1,200-2,500 nautical miles) made it necessary for the subs to patrol near the Soviet Union to increase their striking distance inland. 6 The Polaris submarine facilities at Holy Loch eliminated the need for patrolling SSBNs to return to the continental United States to re-arm, re-supply, or swap crews. The ability to be supported close to the patrol areas of the North Atlantic maximized time spent on alert status as well as reduced the wear and tear on the propulsion plant of the submarine, thus extending the service and maintenance cycles for each boat. Holy Loch was critical in maintaining a forward nuclear presence, the high frequency of Polaris deterrent patrols, and the boats' overall effectiveness. When the Skybolt program failed and was cancelled, the United States was faced with having to provide the United Kingdom with a commensurate alternative to retain the use of the vitally important Scottish port. 7
The political implications and consequences for not providing an alternative to Skybolt were significant. The United States' failure to follow through with its agreement would severely damage relations with the United Kingdom and also endanger the credibility of the U.S. alliance system. 8 Polaris was thought to be a viable alternative as the United States had already offered its use to NATO countries both as a land-based medium-range ballistic missile (MRBM) and through a proposed surface ship-based program. Providing the British with an SLBM for integration with their SSBNs would complement the United States' commitment of Polaris submarines to NATO. Since the British had already phased out their own air-launched MRBM programs in favor of Skybolt, and both countries predicted the near-future phasing out of strategic bombers, Polaris would be the only viable and lasting alternative. 10
Extra Targeting Coverage
The final decision to give Britain Polaris was left to President John F. Kennedy, who agreed to do so. The United Kingdom would assign its missiles and submarines to NATO for the defense of Western Europe, deemphasizing their role as a national nuclear deterrent. The United States thus was able to encourage the development and support of a multinational force in NATO without upsetting other European allies. 11
The United States saw a significant benefit in the UK Polaris missiles assigned to NATO. Because the United States provided NATO with all of its nuclear targeting data, it would effectively control the targeting of the additional Polaris missiles, and their sale would indeed directly help combat the Soviet threat.
The United States was providing NATO with a list of targets to be used in the organization's strategic Nuclear Operations Plan (NOP), with the Supreme Allied Commander, Europe and the Nuclear Planning Group approving the target lists, their implementation, and overall strategy. Those targets were taken from the National Strategic Target List and coordinated with the United States' Single Integrated Operations Plan (SIOP), which "assigns targets to all strategic weapons systems." 12
Under two separate plans—the U.S. SIOP and NATO NOP—no single target would be assigned to both forces. Thus, the United States was providing the targeting for its own Polaris missiles through the SIOP while simultaneously providing the "NATO designated" targeting for the United Kingdom's Polaris missiles. This reduced the number of targets to be covered by U.S. national strategic assets.
The end result of U.S. control over targeting was that the United Kingdom paid for the missiles and the support, development, and maintenance of a launching platform, while the United States was ultimately ensuring that the missiles' warheads provided desired coverage for targets from the strategic list without using U.S. nuclear assets. Although the United States did not control the United Kingdom's Polaris submarines, ownership did not necessarily matter since the warheads were targeted to benefit U.S. nuclear strategy through NATO.
The 'Moscow Criterion'
It is important to note that British Polaris submarines did, however, carry two sets of targeting tapes. The primary tapes supported NATO targeting data and strategy, while the second set was strictly of British origin and development under the "Moscow Criterion"—the ability of the UK to strike the Moscow area to destroy Soviet leadership. 13 Although the United Kingdom's SSBNs carried targeting tapes that benefited British national nuclear strategy, under the Polaris Sales Agreement, they were only to be used in an absolute dire national emergency. 14 Thus, the missiles and targeting tapes themselves were primarily used in support of NATO strategy.
By having targets from its target list designated and assigned to NATO forces, in particular British Polaris missiles, the United States gained additional coverage of Soviet targets without expending its own funds. A British launching platform created an additional military and intelligence dilemma for the Soviet Union, forcing it to exhaust further resources trying to combat two Polaris forces. Finally, the sale of Polaris strengthened Anglo-American political relations, and, ultimately, contributed greatly toward combating the Soviet threat and winning the Cold War.
1. Project Naboska: The Implications of Advanced Design on Undersea Warfare, 1 December 1956, U.S. Nuclear History, National Security Archives, Washington. At https://nsarchive.chadwyck.com  ., p. 14.
2. Overall Strategic Concept for the Defense of the North Atlantic Treaty Organization Area: Final Decision on MC 14/2, 21 February 1957, U.S. Nuclear History, National Security Archives, Washington. At https://nsarchives.chadwyck.com.;  pp. 11,15, 20, 30.
3. William Burr. U.S. Nuclear History: Nuclear Arms and Politics in the Missile Age 1955-1968, Guide and Index (Washington: The National Security Archive and Chadwyche Healey, Inc., 1997), p. 93.
4. Beatrice Heuser. NATO, Britain, France and the FRG: Nuclear Strategies and Forces for Europe, 1949-2000 (New York: St. Martin's Press, 1997), p. 28.
5. Memorandum from President Eisenhower to Prime Minister Macmillan, 29 Mar 1960. Foreign Relations of the United States, 1958-60, Volume VII, Part 2, p. 863
6. U.S. Navy Department: Strategic Systems Programs. Strategic Systems Programs: Facts/Chronology Polaris Poseidon Trident (Washington, DC: Strategic Systems Programs, 2000), p. 2-3.
7. Memorandum: Second Meeting with the President on FY-64 DoD Budget Issues, 23 November 1962. Foreign Relations of the United States, 1961-63, Volume VIII, pp. 415-6.
8. Implications for the United Kingdom of Decision to Abandon Skybolt, 31 October 1962. Foreign Relations of the United States, 1961-63, Volume XIII, p. 1083-4.
9. Eisenhower to Macmillan, 29 Mar 1960, Foreign Relations of the United States, 1958-60, VII, p. 863; Instructions for the Permanent Representative to the North Atlantic Council (Finletter), undated. Foreign Relations of the United States, 1961-63, Volume XIII, p. 410.
10. United Kingdom Ministry of Defense. The History of the UK's Nuclear Weapons Programme, Fact Sheet 5 (London: United Kingdom Ministry of Defense, 2006), p. 1.
11. Memorandum of Conversation: Kennedy and Macmillan, 9:45 a.m., Nassau, Bahamas, 19 December 1962, Foreign Relations of the United States, 1961-63, Volume XIII, pp. 1091-4, 1102-3; Polaris Sales Agreement, 6 April 1963, Washington D.C., p. 2.
12. Desmond Ball. Targeting for Strategic Deterrence, Adelphi Paper No. 185. (London: The International Institute for Strategic Studies, 1983). pp. 9, 15.
13. Shaun Gregory. Nuclear Command and Control in NATO. (New York: St. Martin's Press Inc., 1996), p. 117; Heuser, p. 76.
14. Telegram from the Delegation to the Heads of Government Meeting to the Department of State, Nassau, Bahamas, 19 December 1962, Foreign Relations of the United States, 1961-63, Volume XIII, p. 1107.