As North Korea’s nuclear program advances, many have been asking what Pyongyang hopes to achieve with these capabilities. Although, on balance, most analysts seem to agree that North Korea will primarily use nuclear weapons to deter the United States and its allies from attacking it, others fear a more sinister purpose.

This narrative—which is being championed by some of the best observers of North Korea— contends that Kim Jong-un sees nuclear weapons as a viable way to reunify the Korean Peninsula under his rule. Indeed, according to this argument, Kim Jong-un deems conquering (or at least ruling) South Korea as necessary to cement his legacy alongside his grandfather and father in the annals of North Korean legends. KGS Nightwatch, an indispensable global security newsletter, succinctly summed up this argument recently:

The North Korean nuclear and missile capabilities are components of Kim’s updated reunification strategy.

Kim Jong Un talks and acts as if he believes that under his leadership national reunification is achievable. He would then outdo his ancestors and become the greatest Kim. That is only possible if the US and Japan are deterred from intervening. He and his cohorts apparently judge that they can defeat South Korea if the US and Japan can be neutralized.

I tend to doubt that Kim Jong-un really believes he will be able to use his nuclear weapons to reunify the peninsula. That being said, I certainly don’t claim to know exactly what Kim Jong-un thinks. What is important is that regardless of what Kim Jong-un believes, North Korea will not be able to use its nuclear weapons to achieve reunification.

Instead of talking about the matter in abstract terms, it's useful to begin by looking at history. Besides North Korea, eight countries have built nuclear weapons (nine if you count South Africa). Of these, Israel is the only country who conquered any appreciable amount of territory following their acquisition of the bomb. In this case, nuclear weapons played absolutely no role since no one even knew the Jewish State had the bomb during the 1967 war. On the other hand, some countries—notably the Soviet Union and to a lesser extent France—actually lost territory after building nuclear weapons. This record suggests that nuclear weapons are not a particularly effective instrument for conquering nations. Indeed, as some French leaders argued during the Cold War, an aggressor that wants to conquer another country would not use nuclear weapons since this would destroy its value.

Of course, history doesn’t repeat itself, it merely rhymes. Just because nuclear weapons haven’t proven to be a useful instrument of conquest in the past, doesn’t mean they won’t be in the future. Is there anything to suggest the North Korean case will be different from the ones that came before it?

Far from it. In fact, it’s when you look at the case on its merits that the notion that North Korea can conquer South Korea becomes completely absurd. The first part of Kim Jong-un’s alleged plan is to use his nuclear weapons to force the United States to leave the peninsula. That seems unlikely. First, nuclear blackmail has never proven to be that effective. Moreover, the Soviet Union and China’s acquisition of nuclear weapons did not lead America to retreat from Europe or Asia respectively. And, despite the American First rhetoric in the White House and war exhaustion among the American people, the United States is trying to strengthen its military posture in the Asia-Pacific to deal with China’s rise. South Korea hosts the second largest U.S. presence in the region, and Washington can ill afford to lose its bases in that country. Thus, independent of the North Korean issue, America has a strong and enduring interest in remaining in South Korea.

Nonetheless, for the sake of argument, let’s consider a scenario where the United States did withdraw its military from the peninsula. Then what? North Korea still has to defeat South Korea’s military and pacify its population. That’s a tall order. The Democratic People’s Republic of Korea is one of the most closed and repressive countries in the world. South Korea is a budding democracy and the most wired society in the world. It’s population would have every incentive to resist being absorbed by a Stalinist regime.

They’ll also have more than enough firepower to defeat the North Korean menace. To begin with, South Korea’s population is twice the size of its northern neighbors. North Korea’s economy is not even one percent the size of South Korea’s, and Seoul spends at least ten times as much on its military each year. Although North Korea could cause immense damage to South Korea through artillery and other attacks, it is nearly inconceivable that it could defeat the South Korean military, conquer the country and rule its population. And that’s even assuming South Korea does not build nuclear weapons, which it could do relatively quickly if need be.

Of course, none of this happens automatically, and it is important that the United States and South Korea actively work to persuade Kim Jong-un that the peninsula will never be united under his rule. For instance, Kim Jong-un almost certainly wants to break the U.S.-South Korean alliance, and it is important that Washington and Seoul make abundantly clear that this is not possible. Moreover, some observers fear that—if the United States leaves the peninsula—North Korea will slowly absorb South Korea through a federation, similar to what China is doing in Hong Kong. I find this scenario to be extremely unlikely because, as noted above, it’s hard to envision the South Korean people willing to live in a closed off Stalinist society. If anything, one would think Kim Jong-un might be worried about his ability to rule over North Koreans if they personally saw how much better their southern brethren live. Indeed, in the China and Hong Kong parallel, South Korea is more likely to be the China and North Korea the Hong Kong. Still, South Korean progressives would be wise to ignore North Korea’s offers to establish a confederation. These proposals are made with the worst intentions in mind.

Zachary Keck (@ZacharyKeck) is the Wohlstetter Public Affairs Fellow at the Nonproliferation Policy Education Center.