It is an undeniable fact that the recent US-North Korea summit provided a turnaround in the nuclear standoff between the two sides. But the dramatic shift from threats of war to handshakes for peace did not come without defects. US President Donald Trump’s rash move that could weaken the South Korea-US alliance is one of them.

What Trump said -- he gave the same words to Kim Jong-un during their talks in Singapore earlier this week -- is already seeing repercussions, as his pledge to cease the South Korea-US joint military exercises could shake the foundation of the decadeslong alliance between the two countries. Moreover, he made it clear he wanted to pull back American troops from South Korea eventually.

Obviously, Trump tried to kill two birds with one stone: He used the US forces in South Korea as a negotiation tool with Kim in Singapore and at the same time equated it with his populist “America First” policy.

His double intention was clearly disclosed in his news conference statement in which he said the US would be stopping joint drills with the South because they are “provocative” and require “tremendous expenses.”

His position that the joint military drills between South Korea and the US -- mostly defensive in nature -- are provocative is exactly what the North has long insisted.

In fact, the North Korean state media reported Kim demanded to Trump that the US side stop its acts of hostility. The North made the same demand in the inter-Korean generals’ talks held at Panmunjeom on Thursday. As expected, President Moon Jae-in indicated he would agree with Trump on the joint exercises.

By promising to stop the joint military exercises without a parallel action on the North’s part to reduce security tensions on the peninsula, Trump surrendered a good negotiation card. No wonder his reckless, premature move has been under heavy fire from members of the US Congress, media and experts on North Korea.

Trump also ignored the fact that the security threat from the North comes not only from its nukes and missiles, but also its conventional war capability, which is at a top level on a global scale.

As a matter of fact, the joint military exercises have little to do with the North’s nuclear threat, although the drills were elevated when tensions rose over the North’s nuclear and missile provocations. What also should be noted is that in principle, the alliance means if one party is invaded, the other comes to its aid by participating in the conflict, and such joint operations are impossible without adequate prior training.

Another ugly aspect of the “Trumpian way” that was highlighted in Singapore was that he was preoccupied with the economic calculation of the alliance with South Korea and the denuclearization work, for which he emphasized the financial role of both South Korea and Japan.

It indeed was pitiful that Trump even mentioned the money needed for the six-hour flight of US strategic aircraft from Guam to Korea. It was ill-fitting for the leader of the world’s most powerful country, who was setting out on a historic mission to resolve a security threat his predecessors apparently could not.

There is no doubt that one of the goals of the US military stationed in South Korea is to deter provocation from the North. But along with the American troops in Japan, the US forces in South Korea play greater geopolitical roles, like checking the military expansion of China in the region.

That means the issue of reducing the strength of US forces in South Korea -- either a comprehensive halt to joint drills or eventual drawdowns -- is not a matter to be decided without careful consideration.

Most of all, a drastic change to the status of the US forces in South Korea should never be made before achieving the complete, verifiable and irreversible dismantlement of the North’s nuclear capability and a significant reduction in threat from the North’s conventional forces.