So, yesterday afternoon, the Commander-in-Chief sent this on his personal social media platform:

NYT (“Trump Orders Pentagon to Curtail Military Exercises With Ally South Korea“):

President Trump said on Sunday that he had instructed the Pentagon to reduce joint military exercises with South Korea, a longtime U.S. ally and a linchpin of America’s national security strategy in the Asia-Pacific region.

The announcement may heighten growing worries among Asian allies over what the United States is now willing to do to deter China, given the enormous distraction and resource drain of the U.S.-Israel war against Iran. The United States is running low on critical weapons and has been moving military resources out of Asia to the Middle East.

[…]

The U.S. and South Korean militaries have held joint exercises for more than 70 years, since 1955, after the 1953 armistice that ended the Korean War.

The South Korean Defense Ministry confirmed that the joint military exercises had begun on Monday as scheduled. In a statement last week, the allies emphasized that the 11-day annual Ulchi Freedom Shield exercises were “defensive in nature” and aimed at enhancing the countries’ readiness and capabilities by “incorporating realistic threats, including lessons learned from recent conflicts.”

[…]

The exercises are held most summers with South Korea’s armed forces and with other U.S. allies in the Asia-Pacific region. They focus on how the allied militaries can counter a wide range of security threats, including drones and cyberattacks, while also strengthening combined defenses. They are designed to help U.S. allies defend against threats from North Korea.

The Pentagon was taken aback by Mr. Trump’s sudden announcement, according to a senior U.S. military official. Just last week, an official with U.S. and South Korean Combined Forces Command told reporters that the exercises would simulate combat against North Korean troops, who have gained crucial experience while fighting for Russia in its war against Ukraine.

The move is the latest example of the president appearing to turn against an ally in favor of a leader that previous administrations have cast as an adversary. Trump and others in his administration have also railed against NATO allies over perceived lack of support for his war against Iran, even as they seek to confront an increasingly aggressive Russia in the Baltic region.

It is also a sharp turnaround from how his administration has viewed South Korea in recent months.

In May, Hegseth praised the longtime ally for its “commitment to increase defense spending” and its “leadership in assuming primary responsibility for the security of the Korean Peninsula” during a meeting at the Pentagon.

“It demonstrates alliance burden-sharing that all of America’s partners would do well to follow,” the defense secretary added.

It’s noteworthy that Trump’s post came at 5:04 PM Eastern time, or 6:03 AM Monday morning in Seoul. If the exercise hadn’t kicked off yet, it was about to. It’s very hard, to say the least, to radically restructure an exercise of this magnitude on the fly. Even though these are recurring exercises, months of planning and coordination go into them. Even when coming from POTUS, tweets aren’t self-executing.

As Helene Cooper suggests in her NYT report above, Trump’s perception of his relationship with his DPRK counterpart is perhaps sunnier than it appears from the outside.

In his post Mr. Trump did not mention a rift in relations in 2017, when the North Korean leader called him a “mentally deranged dotard” after Mr. Trump delivered a speech at the U.N. threatening to “totally destroy” North Korea if the United States had to defend itself or its allies.

Certainly, too, the DPRK has launched a significant number of ballistic missiles over and near our allies during Trump’s time in office.

Whether one considers this threatening or disrespectful, I suppose, is a matter of perspective.

As to congruence with the unclassified, public-facing National Defense Strategy released January 23rd, it’s a mixed bag. The first mention of the Korean Peninsula is here:

The DPRK poses a direct military threat to the Republic of Korea (ROK) as well as to Japan, both of which are U.S. treaty allies. Although many of North Korea’s large conventional forces are aged or poorly maintained, South Korea must stay vigilant against the threat of a North Korean invasion. North Korea’s missile forces are also capable of striking targets in the ROK and Japan with conventional and nuclear weapons as well as other weapons of mass destruction. At the same time, the DPRK’s nuclear forces are increasingly capable of threatening the U.S. Homeland. These forces are growing in size and sophistication, and they present a clear and present danger of nuclear attack on the American Homeland. [emphases mine]

So, clearly, the administration sees DPRK missiles as a threat to both the U.S. homeland and to our treaty allies. (It’s worth noting, as a Hawaiian colleague often does, that they have been capable of hitting our 50th state for quite some time.)

Then again, there is the matter of burden-sharing:

As President Trump has made clear, our allies and partners must shoulder their fair share of the burden of our collective defense. This is the right thing for them to do, especially after decades of the United States subsidizing their defense. But it is also vital from a strategic perspective—both for us and for them. And thanks to President Trump’s leadership, since January 2025, we have seen our allies beginning to step up, especially in Europe and South Korea.

[…]

With its powerful military, supported by high defense spending, a robust defense industry, and mandatory conscription, South Korea is capable of taking primary responsibility for deterring North Korea with critical but more limited U.S. support. South Korea also has the will to do so, given that it faces a direct and clear threat from North Korea. This shift in the balance of responsibility is consistent with America’s interest in updating U.S. force posture on the Korean Peninsula. In this way, we can ensure a stronger and more mutually beneficial alliance relationship that is better aligned with America’s defense priorities, thereby setting conditions for lasting peace. [emphases mine]

That’s every mention of the Peninsula in the document.

I suppose one could argue that limiting U.S. support as an exercise kicks off is consistent with shifting the main responsibility for deterrence to the ROKs. But doing so while praising Kim Jong Un might not assure our South Korean allies that we intend to honor our treaty commitments.