Editing Safeguard Program (section)

==History==
===Nike Zeus===
{{main|LIM-49 Nike Zeus}}

An anti-ICBM defensive ABM system was first considered by the US Army in 1955 under the name Nike II. This was essentially an upgraded version of their [[MIM-14 Nike Hercules|Nike B]] [[surface-to-air missile]] (SAM) along with dramatically improved [[radar]]s and [[computer]]s able to detect the incoming [[reentry vehicle]]s (RVs) and develop tracking information while still leaving enough time for the interceptor missile to climb to its altitude. Zeus had limited ''traffic handling'' capabilities, designed to deal with a small number of attacking missiles arriving over a period of as long as an hour. It was calculated that an attack of only four missiles arriving within one minute would allow one of the warheads to pass by while the system was busy attacking others, making it relatively easy to attack the Zeus base. However, in an era when ICBMs cost about the same as a [[strategic bomber]], such an attack would cost an enormous amount.{{citation needed|date=September 2015}}

Through the late 1950s a new generation of much lighter [[thermonuclear bomb]]s cut warhead weight from {{convert|3000|kg}} in the case of the original Soviet [[R-7 Semyorka]] ICBM to perhaps {{convert|1000|kg}}, and further reductions were known to be possible - the US's [[W47]] of the [[UGM-27 Polaris]] weighed only {{convert|330|kg}}. This meant that much smaller rockets could carry these new warheads to the same range, greatly reducing the cost of the missile, making them far cheaper than bombers or any other delivery system. When [[Nikita Khrushchev]] angrily boasted that the Soviet Union was producing new missiles "like sausages", the US responded by building more ICBMs of their own, rather than attempting to defend against them with Zeus. Adding to the problems, as the warhead weight dropped, existing missiles had leftover [[throw weight]] that could be used for various [[Radar jamming and deception#Mechanical jamming|radar decoys]], which Zeus proved unable to distinguish from the actual RV. The Army calculated that as many as twenty Zeus' would have to be fired to ensure a single incoming missile was destroyed.{{citation needed|date=September 2015}}

===Nike-X===
{{main|Nike-X}}

Faced with these problems, both the Eisenhower and Kennedy administrations turned to the newly created [[DARPA|ARPA]] to suggest solutions. ARPA noted that because the decoys were lighter than the actual warhead, they would slow down more rapidly as they reentered the lower atmosphere. They proposed a system using a short range missile that could wait until the warhead was below {{convert|100000|feet|km}} altitude, at which point the decoys would have been ''decluttered''. Desiring to destroy the missile before it was below {{convert|20000|feet|km}} altitude, combined with the {{convert|5|mile}} per second terminal speed of the RV meant there were only 2 to 3 seconds to develop a track and shoot the interceptor. This would demand extremely fast missiles, high-performance radars and advanced computers.{{citation needed|date=September 2015}}

In 1963, [[Robert McNamara]] cancelled the upcoming deployment of Zeus and announced that money would instead be provided for research into this new system, now known as Nike-X. Construction on the new [[phased array radar]] and its associated computer systems began at the MAR-I site in [[White Sands Missile Range]]. MAR could track hundreds of warheads and the interceptor missiles sent to attack them, meaning the Soviets would have to launch hundreds of missiles if they wanted to overwhelm it. And now that decoys were no longer an issue, the cost-exchange ratio fell back to reasonable levels.{{citation needed|date=September 2015}}

The Nike-X developed the same sort of trouble as the Zeus before it. In this case it was ironically due to the Soviet's own ABM system which was very similar to Zeus. To ensure they could defeat it, the [[US Air Force]] began equipping their own ICBMs with decoys, which would defeat the Soviet's Zeus-like system. However, concerned that the Soviets would upgrade their system to Nike-X like performance, they instead began replacing their warheads with lighter ones, and carrying three of them. This meant that every US missile would require three (or six accounting for redundancy) interceptors.{{citation needed|date=September 2015}}

When the same calculations were run for Nike-X, it was calculated that they would have to deploy 7,000 [[Sprint missile]]s, and the cost-exchange ratio was 20-to-1 in favor of the Soviets. When presented with these numbers, McNamara concluded that deploying Nike-X would prompt to Soviets to build more ICBMs, increasing the risk of an accidental war. From this point on, he opposed building a "heavy" ABM system like Nike-X.{{citation needed|date=September 2015}}

===Sentinel===
{{main|Sentinel program}}

In spite of all of these problems, which McNamara repeatedly made public in a series of talks, the Johnson administration was under intense pressure to deploy an ABM system. In 1966 Congress voted to provide deployment funding for Nike-X, although McNamara refused to use it. As the 1967 elections approached, it became clear that this was going to be a major election issue. McNamara proposed arms limitations talks with the Soviets to put upper limits on the numbers of ABMs and warheads, but the [[Glassboro Summit Conference]] ultimately came to nothing.{{citation needed|date=August 2015}}

By late 1967 it was clear the Soviets were not seriously considering limitations, and were continuing deployment of their own ABM system. In September, the Chinese tested their first [[H-bomb]]. McNamara and Johnson seized on this as a solution to the problem; a defense against the tiny Chinese fleet was both technically possible and relatively low-cost. Deploying this system would mute the ongoing debate, even over the long term if the option was open to expand the system to Nike-X coverage levels in the future. On 18 September 1967, McNamara announced the Sentinel program, with 17 bases covering all of the US, along with a total of just under 700 missiles, about {{frac|1|10}} the number in a baseline Nike-X.{{citation needed|date=August 2015}}

Nixon, having campaigned that the Democrats were deliberately dragging their feet on the ABM, inherited the system with his [[1968 United States presidential election|election win]]. He also inherited a massive [[NIMBY]] backlash that blew up in late 1968 when the Army chose to deploy the missiles in suburban locations to allow future expansion to be easier. City-dwellers could tolerate the idea of an armed rocket attack against bombers going on over their heads. They were less comfortable with the concept of nuclear anti-missiles detonating against incoming missiles at low altitudes.{{citation needed|date=August 2015}}

The issue came to a head at a meeting outside Boston, when an estimated 1,000 to 2,000 people showed up to express their displeasure in spite of a raging blizzard. Congressmen were flooded by letters from constituents demanding the sites be moved, and Congress was soon threatening to freeze all additional funds for the system. Nixon announced construction would be delayed while the system underwent a review.{{citation needed|date=August 2015}}

===Safeguard===
The review was completed on 14 March 1969 and announced in a lengthy speech made by Nixon and various DoD advisers. The entire concept was reviewed and all possibilities considered fresh. Among these, the idea of a heavyweight Nike-X-like system was considered, but Defense Secretary [[Melvin Laird]] apparently came to the same conclusion as McNamara before him, stating that the protection the system offered simply didn't justify the cost;

{{cquote|When you are looking toward city defense, it needs to be a perfect or near perfect system because, as I examined the possibility of even a thick defense of cities, I have found that even the most optimistic projections, considering the highest development of the art, would mean that we would still lose 30 million to 40 million lives...<ref>{{cite book |chapter=The President's News Conference  of March 14, 1969 |title=Public Papers of the Presidents of the United States |url=https://books.google.com/books?id=5x3It8ZGQOgC |date=1971 |first=Richard |last=Nixon |publisher=Federal Register Division, National Archives and Records Service, General Services Administration |location=Washington D. C. |page=211}}</ref>}}

However, they disagreed with the concept of a light city defense as well. There was no reason to deploy a system that only worked under contrived circumstances, especially as accepting them as possibilities meant that the enemy was ignoring your deterrent. If that was the case, why have missiles at all? The real issue becomes ensuring they cannot ignore your deterrent, and it was this concept that Nixon chose. Instead of deploying the ABM system to protect cities, the new deployment would protect the missile bases themselves, ensuring that no limited attack could be contemplated. This did not have to be perfect, or even close to it;

{{cquote|When you are talking about protecting your deterrent, it need not be perfect. It is necessary only to protect enough of the deterrent that the retaliatory second strike will be of such magnitude that the enemy would think twice about launching a first strike.{{sfn|Nixon|1971|p=211}}}}