And in 1987, President Ronald Reagan stood at a spot at the Berlin Wall near where Kennedy stood in 1963 and delivered the famous line: "Mr. Gorbachev, tear down this wall!" And just over two years later, the Berlin Wall indeed fell.
Now it's 2017, and North Korea, South Korea, and the entire world need to see and hear a clear message of American resolve in the face of tyranny and nuclear brinksmanship. Otherwise, the kind of blackmail Kim Jong Un is trying to orchestrate may never end or could be copied by the world's other rogue nuclear club members.
Remember that a big part of the North Korean nuclear threat has been based on that nation's desire (along with a similar hope from a more adventuresome China) to somehow drive the U.S. military presence further from the region. And while increasing our military presence in the South China Sea and closer to the Korean Peninsula will go a long way towards proving that Pyongyang's gambit is a loser, the world needs something more than increased naval and air force deployments. It needs a strong message from the most listened-to man in the world right now.
Sure, President Trump often seems like he belongs more on an episode of TMZ than making an appearance at the DMZ. But he's still the Commander-in-Chief of the most powerful armed forces on the planet. First, stepping out from behind his twitter account and speaking in front of the 37,500 American personnel stationed there will at least give them the message they need to hear as they face what is a growing threat every day. And that message is that their country and its leader haven't forgotten them.
Second, it will continue to portray President Trump as unafraid in the face of personal danger. The White House might want to leak a few more of those reports about fears for his safety just to play this up even more. For all his bravado and threats, would Kim Jong Un make a speech at his side of the DMZ and allow the free news media to cover it? Not likely.
A speech at the DMZ would give President Trump another chance to make his case for standing up to Kim without resorting to insults.
So, what should he say exactly?
President Trump must simultaneously stare down Pyongyang's threats and assure the North Koreans and the rest of the world that we seek peace as the best alternative. Perhaps President Trump's memorable line could be: "Mr. Kim drop your weapons and embrace peace."
Appealing to the basic needs of the North Korean people is the most important key to any Trump message. Now that China is coming more and more on board with trying to defuse the situation, conditions in the regime appear to be particularly dire. These economic challenges paired with the clear symbol of U.S. resolve in the form of a Trump visit and speech at the DMZ could be all that's needed to get Pyongyang to make a major concession.
And comparing what will and won't work for North Korea is so important, because there's little evidence that the Trump team is really set on forcing regime change or pushing for a reunification of the Korean peninsula. In return for humanitarian aid on a massive scale, President Trump should demand a reasonable dismantling of Kim's nuclear program and a reliable and permanent inspection program.
And there's one more thing President Trump should demand: Access. Somewhere in that speech, he should challenge Kim to allow the North Korean people to hear his words without any filters or prior editorializing by Pyongyan's censors. "Mr. Kim, let your people hear my message of peace and freedom or forever resign yourself to the ranks of the enemies of freedom and decency."
No, even the most eloquent and stirring speech from this president won't suddenly reverse his low approval ratings and usher in some kind of American unity behind the White House. But it should provide something perhaps even more valuable for everyone: Clarity. Because it's been the president's many mixed and oftentimes fuzzy messages that may be hurting him more than any one controversy.
Of course, the other possibility is that the North Korean regime can only be forced to back down by military means. But that only makes a possible presidential trip to the DMZ more important. The troops who would be asked to go into harm's way at least deserve the courtesy of not only a personal visit from President Trump but a clear explanation of the purpose of their mission.
The hard truth is that the North Korean nuclear problem is the biggest and most immediate threat to the free world right now. And if the leader of the free world doesn't take his best opportunity to prove he is not afraid to stand up for freedom and real peace, then all of our troubles will only multiply in the months and years to come.
Commentary by Jake Novak, CNBC.com senior columnist. Follow him on Twitter @jakejakeny.
For more insight from CNBC contributors, follow @CNBCopinion on Twitter.