Key point: These are just five ways a second war would be different from the first. Let's hope it never happens.

If a Second Korean War were to erupt tomorrow, there is one thing we can be sure of.

It won’t be like the First Korean War of 1950-53.

It's always reassuring—and usually fatal—to assume a conflict will be like its predecessor. France lost in 1940 because they assumed World War II would be fought in the trenches like World War I. Israel almost lost in 1973 because they assumed the Arab armies would collapse as they did in 1967.

So what are the chances that Korean War II would be just like Korean War I? The answer is, slim to none. Here are five key differences:

1 - No Blitzkrieg

The popular image of the First Korean War is of stalemate, as entrenched armies battled over obscure hills worth nothing more than a notation on map. But the first year of the Korean War was as fluid as any World War II campaign. The conflict began in June 1950 with North Korean tanks and infantry pushing weak South Korean defenders and a scratch American task force 300 miles down the peninsula, from the 38th Parallel to Pusan. Then in September, it was the turn of the North Koreans to flee all the way up the peninsula to the Chinese border after U.S. Marines landed behind their lines at Inchon. Then in November, 300,000 Chinese “volunteers” sent the UN armies in North Korea “bugging out” way down south (seeing a pattern here?). Then in the spring of 1951, the Americans launched a series of methodical high-firepower offensives that pounded Communist forces back across the 38th Parallel once and for all.

So much for stalemate. However, Korean War II won’t be nearly as mobile. The biggest reason is the size of the opposing forces. South Korea now has more than 500,000 well-armed active-duty soldiers as opposed to 95,000 poorly trained soldiers in 1950, backed by 37,000 U.S. troops. That’s a hefty force, but still half the size of North Korea’s 1.2-million-strong army backed by 21,000 artillery pieces. And much of it packed along a Demilitarized Zone that is just 250 miles long. A surprise North Korean tank-infantry assault across the DMZ, covered by a massive artillery barrage and special forces raids, is arguably powerful enough to punch through the border defenses and reach Seoul. But with so many troops stuffed in so small a battlefield, and considering how urbanized South Korea has become over the past sixty-seven years, the offensive will be a bloody slog rather than a blitz. Conversely, a U.S./South Korean drive across the 38th Parallel to Pyongyang would have to penetrate the same bloody hills of 1950–53, but this time even more heavily fortified.

Whether Korean War II would drag on into a permanent stalemate, given North Korea's economic fragility and Western reluctance to endure yet another “long war,” is another matter. Yet barring a collapse of Kim Jong-un’s regime or its army, it seems unlikely there will be any lightning advances or bug-out retreats up and down the Korean Peninsula.

2 - The War Will Be High-Tech

Korean War I was arguably the first conflict of the Cold War. Yet despite some new weapons, notably jet fighters, most of the equipment used by both sides was World War II leftovers such as T-34 tanks and P-51 Mustangs. There was no technology to break the stalemate, short of atomic weapons. However, another Korean conflict would feature the most advanced weapons—at least on the Allied side—such as stealth aircraft, precision-guided missiles and bunker-buster bombs (but hopefully not nuclear weapons). As for the United States conducting an Inchon-style amphibious landing to break a stalemate along the DMZ, any landing would face North Korean access-denial weapons such as submarines, mines and anti-ship missiles. Technology won’t change the need for boots on the ground to achieve any decisive solution in Korea, but it will certainly change the character of the fighting from 1950.

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3 - America Won’t Be Fighting China

This is arguably the biggest difference of all. In many ways, the Korean War should have been called the China-America War, which just so happened to be fought in Korea. It’s hard to conceive of 300,000 Chinese troops streaming across the Yalu to save Kim Jong-un from the imperialists. But if China does intervene...well, best not to think about it. The United States does not want to fight a land war with China on it’s doorstep. China doesn’t want to fight a nuclear-armed superpower that also its biggest economic customer.

4 - America’s Army Won’t Be Draftees

The United States drafted 1.5 million men during the Korean War and mobilized reservists, many of whom had already fought in World War II (and weren’t thrilled about having to fight again). This time, the United States will field a volunteer force: even reinstating the draft could not train enough soldiers in time to make a difference. A professional army creates fewer political problems, but it also means the U.S. military will continue to be overstretched between its European, Middle Eastern and Asian commitments.

5 - North Korea Has Nukes

North Korea wasn’t a nuclear power in Korea War I. It is now. The prospect of weapons of mass destruction being used on the battlefield will be greater than in 1950, when Gen. Douglas MacArthur urged that atomic weapons be used in Korea. This is bound to affect the conflict, such as the inevitable operations to seize or destroy North Korean WMDs.

Yet here, at least, is a similarity between 1950 and 2017. Even in the darkest hour of the First Korean War, President Harry Truman kept his eye on the prize—not triggering World War III with the Soviet Union. Despite MacArthur’s vitriol, Korea was simply not worth the risk of using atomic bombs. Today, North Korea has a nuclear arsenal, which it cannot use without literally facing thermonuclear annihilation. The United States has nukes, but what U.S. president wants to go down in history as the person who dropped the first nuclear bombs in combat since 1945?

Korean War II, should it happen, will be a bloody, ugly conflict. But it will not be a repeat of the prequel.

Michael Peck is a contributing writer for the National Interest. He can be found on Twitter and Facebook. This first appeared in 2017 and is being reposted due to reader interest.

Image: Reuters