With the recognized end of the Cold War and the proliferation of tactical ballistic missiles, the administration of President Bill Clinton initially placed greater emphasis upon theater based missile defense systems. With that, national missile defense became more of a technology development initiative.

By 1996, however, national missile defense, or NMD, was again at the forefront. With the Defense America Act of 1995, the republican led congress introduced legislation which sought to deploy an NMD system -- capable of defending the continental United States, Alaska and Hawaii from any launch -- accidental, unauthorized or development - by 2003.

Under this proposed legislation the U.S. would deploy at the earliest practical date theater and national missile defense systems. The ground-based interceptors, deployed as necessary to one or more sites, would be augmented with ground-based radars space-based sensors and a battle management, command, control and communications system.

The Clinton administration countered that an NMD was not immediately necessary, saying, "No rogue nation today has ICBMs; only the established nuclear powers have ICBMs. [and] our ability to retaliate with an overwhelming nuclear response [would] serve as a deterrent."

In 1996, the Department of Defense conducted a ballistic missile defense program review to assess changes in the environment since the bottom up review conducted three years earlier. On April 9, 1996, Under Secretary of Defense for Acquisition and Technology Paul Kaminski issued a letter explaining the results of this program review.

Given the new guidance, Kaminski directed that NMD be designated an acquisition category 1D program, which elevated the milestone decision authority to his office. At the same time, he directed the Ballistic Missile Defense Organization, or BMDO, a predecessor to the Missile Defense Agency, to establish a joint program office for NMD which would report directly to the BMDO director.

The resulting assessment transitioned NMD from a technology readiness program to a deployment readiness program. The NMD deployment readiness program, also known as the "3 + 3" NMD program, challenged the community "to develop and demonstrate a capability in the next three years that could be deployed in the following three years."

After three years, officials would conduct a new review of the program to assess system level capability and the related BMD threat. At that time, the president could opt to deploy the system or continue with system development.

The decision to deploy therefore was deferred to the year 2000 and if the situation warranted the first phase of three phases would be deployed by 2003. Given the administration's strict adherence to the ABM Treaty, the 3+3 design only allowed for a single deployment site the former Stanley R. Mickelsen Safeguard Complex in North Dakota.

The complex was equipped with 100 ground-based interceptors, a ground-based radar, an upgraded early warning radar, an adjunct forward based radar in Alaska and an in-flight interceptor communications for battle management, command, control, and communications the system built upon existing components.

Unlike alternative deployment concepts, however, the 3+3 was designed to provide a defense against a limited attack by a rogue nation or a small accidental launch. In the absence of a perceived threat, the NMD program would continue with an evolutionary development maintaining the ability to deploy within three years of a deployment decision.

The 3+3 program continued until 1999, when Secretary of Defense William Cohen added two additional years to the deployment phase creating a 3+5 plan. Later that year, President Clinton signed the National Missile Defense Act of 1999 which required that an NMD system be deployed "as soon as is technologically possible." Signed into law on July 22, this legislation effectively ended the 3+3 program.