In the wake of President Trump's trip to Asia, with stops in Japan, South Korea, China, Vietnam, and the Philippines, Americans should thank him for remaining true to his America First principles. He gave speech after speech in which he asserted, sometimes to very skeptical audiences, that the age in which U.S. leaders would prize multilateral trade deals over the protection of American jobs and economic interests is over. He also made it clear that the U.S. will act decisively, if necessary, to prevent North Korea from threatening the world with its missiles and nuclear weapons.

Needless to say, many on the left were undermining Trump's credibility as Commander-in-Chief throughout his visit to Asia, and the international media was beating the drum of fake news anti-Trump narratives just like CNN and MSNBC back home, but the President was unmoved. He stood tall and proud on the international stage, and already his tough line is bearing fruit: China has announced that it will ease restrictions on foreign investments in financial firms, and it will make it easier for U.S. auto manufacturers like Tesla to do business there. China knows that Trump is not to be trifled with.

By far the biggest challenge that America faces in Asia, though, is North Korea, and on this front progress is hard to discern. True, there are signs that the Chinese may be increasingly willing to put pressure on the North Koreans to rein in their nuclear and missile programs – North Korea's relative quietude during Trump's visit to the region is a positive sign – but the diplomatic dance over North Korean nukes involving the U.S., both Koreas, Japan, Russia, and China will last, in all likelihood, for years. Only a massive military strike against North Korean nuclear and missile facilities, as well as their air defenses, artillery installations, and cyber warfare sites, could forestall the delicate diplomacy which Secretary of State Tillerson is currently pursuing, and President Trump seems disinclined to use force until all other options are exhausted.

For this reason, it is now more important than ever that we enhance our defenses against nuclear or EMP attacks emanating from North Korea. This is true not just because the casualties and damage caused by such attacks would be catastrophic, but also due to the fact that a robust and credible missile defense capability will strengthen President Trump's hand as he tries to convince rogue regimes like the one in North Korea that threatening the U.S. with ballistic missiles and nuclear weapons is a waste of time. Simply put, if North Korea's long-range missiles can't reach the United States, because our ability to intercept them is proven and reliable, then there is no reason why an impoverished regime should build them in the first place.

Luckily, our country has a panoply of missile defense technologies in place. Some are deployed in South Korea, Japan, and on U.S. Navy vessels in the vicinity. These systems afford our allies considerable protection, but only the Ground-Based Midcourse Defense system (“GMD” for short) based in Alaska and California protects the homeland from long-range ballistic missiles. The good news is that it has achieved a high rate of effectiveness in testing since 1999, and a continuous process of technical enhancement makes it stronger and stronger, year after year. The bad news, however, is that funding for the system was repeatedly cut under President Obama, and right now the system is oriented towards protecting the U.S. from a nuclear missile attack coming from the west — by contrast, an attack that came over the North Pole or from the east would be difficult to parry.

When President Trump defends our national interests on the international stage, his credibility is greatly enhanced by the fact that he wields the strongest sword imaginable: the might of the U.S. armed forces. The ability of the United States to defeat any foe matters little, however, when that foe is potentially deranged, and wants only to inflict maximum harm on the American people. A comprehensive and expanded GMD system, therefore, offers us the opportunity to make the homeland relatively invulnerable to such threats from rogue regimes. An investment, in other words, in the expansion of U.S. GMD capabilities, and in research and development to improve those capabilities, would be one of the best steps we could take to assuring the safety of the American people, and proving the futility of Kim Jong-Un's vicious threats.

As we celebrate President Trump's magnificent and resolute performance in Asia, let us not forget that he and our national security team need the tools to deter any and all foreign threats. In GMD, we have one of the best tools imaginable — the ability to shoot down incoming nuclear missiles. We should strengthen this system where necessary, but above all we should test it and demonstrate its awesome power frequently. By this means, Kim Jong-Un may someday be compelled to recognize that his dream of obliterating an American city with nuclear fire is just that — a dream, or rather a nightmare, that will never, ever come true.

Dr. Nicholas L. Waddy is an Associate Professor of History in the State University of New York and blogs at: