Twenty seven years ago President Ronald Reagan delivered one of the most important speeches in modern history. For almost five decades, Americans had lived under the threat of nuclear war. The arms race had become a stand-off between the superpowers called mutually-assured-destruction, where any nuclear exchange would likely evolve into a full-scale atomic war annihilating the East and the West. President Reagan believed that this was an immoral way to maintain an uneasy peace if there was a more responsible and proportional alternative. On March 23, 1983 he announced that there was. The president concluded that not only were missile defenses feasible, but that they would lessen the threat of nuclear war.

History proved Reagan right on both counts.

The mere suggestion of deploying what President Reagan called the Strategic Defense Initiative (SDI) brought the Soviet to the negotiating table and resulted in the largest reduction of nuclear arms in history. And though, his proposal was denounced by detractors as science-fiction “Star Wars,” in the last decade, the United States has demonstrated that it can build missile defenses capable of destroying enemy weapons in flight before they can result in harm to anyone.

Yet, despite being on the right side of history, Reagan’s vision has not fully been realized—and it is needed more than ever. Countries like Iran and North Korea are actively seeking to build nuclear-tipped intercontinental ballistic missile forces. And, they are not the only dangers. Their arsenals and aggressive atomic diplomacy may prompt other powers to develop nuclear programs, resulting in a new global arms race. Additionally, both Iran and North Korea are known proliferators of weapons material and technology. For all these reasons, missile defense is more important than ever.

The Heritage Foundation, which sponsored the 1982 High Frontier study (which first made the case that missile defenses were essential and achievable), has long worked to help realize President Reagan’s vision of eliminating the threat of nuclear missile attack forever, by rendering this threat obsolete. Today, the foundation remains on the fore front of public policy research on the vital issue, including producing the groundbreaking documentary 33 Minutes. The film makes the case that the Congress and American people should demand that our government “finish the job,” build robust, comprehensive missile defenses now—not just to defeat existing threats but to preempt America’s enemies from ever believing that could hold the lives of Americans hostage with the menace of nuclear attack.

On this day, it is worth stopping to recall Reagan’s monumental vision and to ask—why isn’t Washington doing everything possible to make it a reality?