You probably didn’t hear about the latest test of the U.S. missile-defense system. And that’s just the way the military wanted it.

Not because it was bad news. Far from it. When two interceptors were fired from Vandenberg Air Force Base in California against an intercontinental ballistic missile-class target launched from Kwajalein Atoll in the Pacific Ocean, they scored a direct hit — exactly as they were designed to do.

It’s another vindication of the philosophy behind the Strategic Defense Initiative (SDI). In fact, the March 25 test came just two days after the 36th anniversary of when President Reagan gave his famous SDI address from the Oval Office.

He took a lot of heat for proposing what was then derided as “Star Wars.” Critics insisted you couldn’t hit “a bullet with a bullet.” But as usual, betting against American willpower and technology proved to be a losing position.

You’d think they would have learned after the moon landing, but no. For some people, it’s too important to score political points than to dream big.

That’s exactly what Reagan did. In his address to the nation on March 23, 1983, he said:

“What if free people could live secure in the knowledge that their security did not rest upon the threat of instant U.S. retaliation to deter a Soviet attack, that we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies?”

The arguments against SDI were always flimsy. Sure, it would take time, effort, patience and a lot of trial and error to get it right. But that’s the kind of challenge Americans have always thrived on.

And when the stakes are so high — life and death, quite literally — why wouldn’t we try? Would those who decried SDI prefer the alternative?

For decades, the world lived in a kind of lethal detente. Throughout the Cold War, the United States and the Soviet Union built up vast arsenals of missiles both big and small. Peace (if you could call it that) was kept through a situation known as Mutually Assured Destruction.

It hardly seems coincidental that the acronym was MAD. Was living with each country holding a gun to the other’s head the best we could do?

Reagan didn’t think so, thank God. As defense expert Michaela Dodge noted recently:

“Monday’s test validates the wisdom of his vision born from the Strategic Defense Initiative program. The Ground-Based Midcourse Defense system is currently the only system protecting the United States against long-range ballistic missiles, such as those that North Korea periodically threatens to use against us.”

It’s a good thing Reagan ignored his critics and pushed ahead. It took time to get to this point — more time than it likely would have in the past.

Perhaps that’s because we’ve become so risk-averse as a society. As Air Force Gen. John Hyten, commander of the U.S. Strategic Command, put it: “I don’t know how it happened, but this country lost the ability to go fast.”

That’s unfortunate. As Ms. Dodge points out, we sometimes learn more from failure than from success.

“It is better to design missile defense tests in a way that pushes the system’s envelope, even if it means a higher likelihood of a failure,” she writes. “It is better that a system fails during a test, rather than in a real-life situation when it’s too late to improve upon it.”

But we’re working toward success, of course, so when those moments come — when we stage a test that works — we deserve to enjoy that victory. “My fellow Americans, tonight we’re launching an effort which holds the promise of changing the course of human history,” President Reagan said. “There will be risks, and results take time. But I believe we can do it.”

We can. We are. So let’s press on — and continue building on the incredible success that Ronald Reagan and other early advocates of missile defense left us as our bedrock legacy.