Over the last several decades, missile defense has been pursued by some as a dream and scoffed at by others as a boondoggle; thankfully, today it’s a reality. The Ground-Based Midcourse defense system – GMD for short – can intercept nuclear ballistic missiles outside the earth’s atmosphere, destroying them in a precise, head-on collision.

The operational system has a strong track record in recent tests, during which the crew has just minutes to identify, track, and shoot the target missile down without knowing when or where it will be launched. And despite the assertions from critics that countermeasures like balloon decoys could fool the system, the GMD tracking system has never mistaken a decoy for the real McCoy in tests involving countermeasures.

Housed in silos in California and Alaska, 20 operational GMD interceptors extend a defensive shield over the U.S. mainland. Although that’s 10 short of the number the Obama administration has pledged to build and less than half the originally planned number, it is a critical defense that we should continue to improve.

The cost of improvements is miniscule compared to the value of the missile shield. The entire GMD budget is less than one twentieth of one percent of the federal budget (by contrast, entitlements make up roughly 40%). Cutting the missile defense budget will make us vulnerable to attack, but it won’t save much money.

That’s why it’s so frustrating that Congress may cut the system simply due to political gridlock.

Unless Congress intervenes, a process known as “sequestration” will automatically cut $600 billion from the defense budget by slashing the top-line of every Pentagon program, including armor for our troops, drone aircraft to fight terrorists, and missile defense. By cutting the essential along with the inessential programs, “this kind of massive cut across the board…would have devastating effects on our national defense” according to Defense Secretary Leon Panetta.

These budget cuts could delay or even cancel the construction of additional interceptors to protect us from the growing ballistic missile threat from North Korea. It could dry up money to install interceptors on the East Coast to defend against the looming threat from Iran. And it could scuttle ongoing tests to improve the system’s defenses against increasingly sophisticated ballistic missiles. The sequestration cuts will ignore the expert intelligence that makes the case for these improvements and cut blindly, leaving us vulnerable in the near future for no good reason.

The same year WarGames hit theaters, then-President Ronald Reagan announced his plan to develop missile defenses to protect us from the very real threat of nuclear attack. Now that missile defense is a reality, Congress should protect it and the nation’s other essential national security programs.

Adrian Cronauer is a former United States Air Force sergeant, Vietnam War veteran, attorney and radio personality best known as the inspiration for Robin Williams’ character in the 1987 film “Good Morning, Vietnam.”