It was 25 years ago this month, in a presidential address from the Oval Office, when Ronald Reagan asked this question:
"What if free people could live secure in the knowledge that we could intercept and destroy strategic ballistic missiles before they reach our own soil or that of our allies?"
President Reagan never used the words, but this will forever be known as the "Star Wars" speech, a term of gentle derision for his vision of battle stations in space destroying Soviet missiles with lasers.
It never happened, but today there is a scaled-down version of Star Wars, not in space but on Earth - interceptors to defend not against an all-out Soviet attack, but against a handful of missiles launched by North Korea or Iran.
"If you want to call it Star Wars lite," Lt. Gen. Trey Obering told CBS News correspondent David Martin, "I have no problem with that term."
Obering is the man in charge of building a system that can shoot down incoming ballistic missiles - the proverbial "hitting a bullet with a bullet."
"I was a big fan of the 'Star Wars' movies," Obering told Martin, "and when you think about what that was involving, it was, I think, the force of good versus the forces of evil in the universe."
Obering's forces of good include a giant radar floating on an oil platform in the Pacific Ocean; nearly two dozen interceptor missiles in underground silos in Alaska and California; and still more interceptors on Navy cruisers. One of those blew up that out-of-control satellite a few weeks ago - the first real shootdown by a system that to date has cost $115 billion, but which most Americans don't even know exists.
Martin asked Obering straight out if the U.S. currently has a missile defense system.
"Yes sir," he answered. "We have a missile defense system today."
"As we're speaking," Martin pressed him, "someone is sitting at a screen watching for that North Korean missile?"
"Yes sir, that's a fact. We have crews on alert."
"This may be one of the best kept secrets in Washington," Martin told him.
"Yes sir," Obering agreed.
Cheyenne Mountain was built deep underground in the 1960s with 25-ton blast doors to survive a Soviet nuclear strike. Today it's headquarters for defending the U.S. against a North Korean missile attack.
Located in the Colorado Rockies, the alert center at Cheyenne Mountain would get the first warning of a missile launch from a satellite whose infrared sensors can detect a rocket plume as it lifts off the pad. Since some 30 countries have ballistic missiles, Lt. Col. James Cobb says, test launches happen all the time.
"Good days you can have five or six," Cobb explained, "You can go several weeks without any."
"Somewhere in the world," Martin asked.
"Anywhere in the world," Cobb told him.
As the missile climbs into the sky, it will be picked up by radars and Cobb will have just minutes to determine if it's a threat to the U.S.
"I can tell you where it came from and where it's pointed," he said.
Computers predict the trajectory of the missile.
Martin asked Cobb what the red dot indicated on the radar equipment.
"That would be North Korea," he answered.
"So," Martin asked, "if a missile were fired from North Korea, then that box, or the long rectangle, would be where it could come down."
"The 'threat area' is how we refer to it," Cobb explained. "If you look there's a little triangle in Alaska. That's the predicted impact point."
Once a missile launch is detected it would take about 45 minutes for it to land on U.S. soil, although the attempt to shoot it down must be made much faster than that.
Twenty miles away, at Schriever Air Force Base, a 5-man team would track the incoming warhead and attempt to shoot it down with those interceptors in Alaska and California.
Since the chances of a bolt out of the blue attack are exceedingly low, the team headed by Lt. Col. Terrance Douglas spends most of its time on watch practicing.
Martin asked Douglas how much time his team spends on practice exercises.
"We'll do anywhere from 3 to 7 during our shift," he said.
In this exercise, three missiles are headed toward the U.S.: one for Dallas, another for San Francisco and the third for Seattle.
"You're looking up there and it's like a video game," Martin observed. "But if it were the real thing, you guys would be playing for all the marbles. This would be it."
"This particular job here is amazing," Douglas told him. "You're protecting millions of folks because of what may be fired at them and they wouldn't know it. They'd just be walking down the street and wouldn't know it. Have no idea."
It's an exercise. No real missiles are fired by either side and it all goes like clockwork.
Martin asked the Pentagon's former chief weapons tester Phil Coyle if the missile defense system that we have today would be able to defend against that kind of attack demonstrated in the practice scenario.
"Unfortunately," Coyle said, "it wouldn't."