Donald Trump and Kim Jong-un are engaged in a game of intimidation and one-upmanship that has China, desperate for stability on the Korean peninsula, warning that tensions could spin out of control. Kim, audaciously pushing the envelope, and Trump, the beneficiary of a tutorial from Chinese President Xi Jinping, may yet escalate from rhetoric to action.

While Trump’s top lieutenants, Defense Secretary James Mattis, Secretary of State Rex Tillerson and National Security Adviser HR McMaster, are considering “options” including a “preemptive” strike on the North’s missile and nuclear test sites, North Korea’s leader is warning of a preemptive strike of his own.

Nonetheless, on the streets of Seoul, in bars and coffee shops, no one seems too worried that Armageddon is at hand despite the fact that the South Korean capital is just 55 km. from the Demilitarized Zone.

True, on the other side 300 ballistic missiles plus thousands of artillery pieces are aimed at the Korean capital and the nearby port city of Incheon, but North Korea is not topic A on lists of talking points. Generally, it’s not discussed. The only ones who seem genuinely interested in North Korea are the four candidates running for president of South Korea in the snap election on May 9 - plus analysts and journalists who can’t stop talking and writing about it.

That doesn’t mean, though, there’s nothing to worry about. An armada led by the aircraft carrier USS Carl Vinson serves as a reminder of American power. Originally reported off the Korean peninsula, the Carl Vinson group is expected to return to the western Pacific after joining in exercises off Australia. Images of warplanes roaring off the deck recall the Korean War when General Curtis Le May ordered bombing that destroyed just about every North Korean city and town.

Could it happen again? These days, as shown in the attack that Trump ordered on the Syrian air base in retaliation for Syrian President Bashar al-Assad’s alleged chemical attack on hapless civilians, cruise missiles are an invaluable asset. They not only travel long distances but are devastatingly accurate. A cruise missile could hit a launch site just about anywhere in North Korea, probably destroying it or at least making it impossible, temporarily, to launch a missile.

President Trump is learning, however, that getting tough on North Korea is easier said than done. He got some insights in his wide-ranging conversations with Xi at his Mar-a-Lago estate last week. As Trump acknowledged in an interview with the Wall Street Journal, “I realized it’s not so easy.” Yes, he had once “felt pretty strongly” that the Chinese “had tremendous power” over the North – “but it’s not what you would think.”

So how much do the North Koreans have to fear from the US? They observed the 105th anniversary this weekend of the birth of Kim Il-sung, grandfather of Kim Jong-un and founder of the regime that has ruled North Korea since 1945, in a style designed to prove they were more than ready for whatever Trump might have in mind.

This was the “Day of the Sun,” the biggest holiday on the North Korean calendar, but it was no ordinary celebration. Not since October 12, 2015, the 100th anniversary of the founding of the Workers’ Party, had Kim Jong-un ordered such an impressive display, a military parade bristling with missiles. In a black business-like suit, Kim presided over a review of missiles, cannon, armored vehicles and goose-stepping troops while Choe Ryong-hae, a vice chairman of the Workers' Party, vowed the North would respond to “nuclear attacks with nuclear strikes."

More intimidating than the rhetoric is the weaponry, including what looks like a new intercontinental ballistic missile capable of firing a warhead as far as the US west coast plus prototypes of submarine-launched intermediate-range missiles. North Korea didn’t have to stage its sixth nuclear test, as widely predicted, to prove its defiance of UN sanctions – and of the increasing possibility that the US is ready to fire first.

But where is the red line? Does Trump have any idea – or would he act on gut instinct as in ordering the Syrian strike? And might he or Kim Jong-un simultaneously suddenly lose patience or misinterpret the intentions of the other side?

For Trump, the moment of reckoning would surely come if Kim ordered the test-firing of a long-range missile that flew a considerable distance over the Pacific or put a satellite into orbit. Trump before his inauguration in January almost dared the North Koreans to test the missile, famously tweeting: “North Korea just stated that it is in the final stages of developing a nuclear weapon capable of reaching parts of the US! It won't happen!”

Did Trump mean he would annihilate the missile site preemptively – or would he order its destruction after North Korea conducted the test? For that matter, does Trump himself know? His remark, as reported in the Wall Street Journal, that he became aware of some of the realities in ten minutes of talk with Xi Jinping suggests an astonishing lack of understanding of the difficulties in pressuring North Korea.

While the North Koreans were staging their parade, US and South Korean troops were going through their annual war games, featuring live-fire near the Demilitarized Zone. Reporters were invited to watch several thousand US and South Korean troops stage a logistics exercise on the beach near the east coast industrial city of Pohang that showed how fast they could unload heavy equipment anywhere from ships off-shore –the kind of expertise needed to invade the North.

US Brigadier General Michael Russell called the exercise an example of the “ironclad” bond between the US and South Korea and “our ability to flawlessly execute capabilities,” but South Koreans wonder if the US would consult with their leaders before attacking the North. Or would Trump act unilaterally while US diplomats and military officers would have to go around telling aggrieved South Koreans what the US was doing?

South Korea indicated the current government might not be averse to a preemptive strike after the North test-fired a mid-range missile the morning after the parade. Yes, the latest missile-firing ended in failure when it exploded shortly after launch, but the South’s foreign ministry said the North’s “show of force threatens the whole world.”

The question of how to respond is highly sensitive in campaigning for a presidential election in which the leading candidates, Moon Jae-in of the Minjoo or Democratic Party and Ahn Cheol-soo of the Kookmin Dang or People’s Party, have opposed a preemptive strike.

The US command, moreover, abruptly canceled an invitation for reporters to witness planes, tanks and infantry troops at a range close to the DMZ.

On that day, Trump was to receive China’s President Xi Jinping at his Mar-a-Lago estate. The White House did not want the exercise upstaging efforts to get China to “do something” about North Korea while telling the Chinese, yet again, that the reason for planting a battery of missiles in South Korea called THAAD for Terminal High Altitude Area Defense was to shoot down high-flying North Korean missiles – nothing to do with China.

As Xi was leaving, of course, came the news of Trump’s strike on the Syrian air base. Would North Korea be next? As the Carl Vinson armada steamed off the Korean coast, the second Korean War seemed closer than ever – though somehow it all seemed a little unreal.