Trump described North Korea's pursuit of nuclear missiles as "reckless" and said there is a campaign of "maximum pressure" to stop it. The administration has also floated the idea of a targeted strike to respond to missile launches and give the regime a "bloody nose" that would — hopefully — not escalate into a wider conflict.
"This puts Moon Jae-in between a rock and a hard place," said Lee Chung-min, professor of international relations at Yonsei University in Seoul, referring to the South Korean president.
Now the Moon government will be trying to talk down a Trump administration that is apparently more serious about giving North Korea a "bloody nose" than analysts realized — at the same time as North Korea is preparing for a huge military parade.
The Pyongyang regime suddenly moved its Army Foundation Day, celebrated for the last 30 years on April 25, back to the original date of Feb. 8.
Satellite photos show preparations for a large parade in Pyongyang, and South Korean officials have said it is shaping up to be "intimidating" in size and weaponry — a display that appears likely to further heighten fears about the regime's intentions.
Then once the Olympic Games are over and joint military exercises begin in South Korea, many analysts think North Korea will protest with a provocative action such as launching another missile.
All this is taking place without a U.S. ambassador in Seoul.
"The role of an ambassador is not nearly as important as it once was, but we will have been more than a year without an ambassador in one of the United States' most important alliances and at a very sensitive time in the region," Lee said.
The Trump administration has abruptly ditched Victor Cha, an academic who served in the George W. Bush administration and is known for his hawkish approach to North Korea, as its candidate for U.S. ambassador to South Korea.
Although his views sharply diverge from the South Korean government's engagement-centered approach, Cha, a Korean American who teaches at Georgetown University and runs the Korea department at the Center for Strategic and International Studies, is well known and well connected in Seoul.
Moon's government signed off on Cha's nomination in December after Washington sent formal notice of intent to nominate him as ambassador, a process known as agrément.
Cha was suddenly withdrawn, however. That happened as he raised concerns about the "bloody nose" idea of a limited strike to send a message without sparking a wider war.
Political analysts across the spectrum generally think this is an ill-advised strategy that could risk the lives of the 25 million South Koreans — and tens of thousands of Americans — who live within North Korean artillery range.
The South Korean president has repeatedly said Trump cannot launch a strike on North Korea without his approval — a statement of hope more than of fact, since the United States calls the shots in their military alliance.
South Korean news sites were full of headlines Wednesday about the "mystery" of Cha's sudden withdrawal from the position — "falling off a horse" in Korean. Media commentary noted how unusual it was for an ambassadorial candidate to be withdrawn after the host government had signed off.
The South Korean government has not been informed of the Trump administration's decision to withdraw Cha as its candidate for ambassador, according to two senior officials.
Having completed the agrément process, Seoul is expecting an explanation from Washington, said one of the officials, who spoke on the condition of anonymity to discuss diplomatic issues. "It's not desirable to not have a fully fledged ambassador at this very sensitive time," said the other senior official.
He questioned whether the administration would be able to find a candidate who was even more hawkish than Cha.
Trump doubled down Tuesday with his tough language against North Korea, saying only heavy-handed measures would work against the regime in Pyongyang.
"Past experience has taught us that complacency and concessions only invite aggression and provocation. I will not repeat the mistakes of past administrations that got us into this dangerous position," he said.
Trump did not specifically mention diplomacy as an option for dealing with North Korea, though his reference to "maximum pressure" could include diplomatic efforts. That language stood out to Duyeon Kim, a fellow at the Korean Peninsula Future Forum in Seoul.
"It almost sounds like he is selling a future war with North Korea much the same way Bush did in his State of the Union on Iraq," she said. "If he is indeed marching the U.S. and the region into a war, this time it would be with a country that actually has nuclear weapons. So that could quickly get out of hand."
For its part, North Korea released its own damning condemnation of Trump on Wednesday. This is a standard regime tactic to try to divert from its own treatment of its citizens.
In a report in its "White Paper on Human Rights Violations in U.S. in 2017," North Korea's state media laid out complaints against the American president, starting with his choice of billionaires for Cabinet posts and his policies to help the rich.
"In the U.S. the absolute majority of the working masses, deprived of elementary rights to survival, are hovering in the abyss of nightmare," the report said, citing youth unemployment and homeless numbers, and the "hell" of student loans.
It also cited a lack of paid maternity leave, sexual assault, gun crimes and marijuana use.
"The U.S., 'guardian of democracy' and 'human rights champion,' is kicking up the human rights racket but it can never camouflage its true identity as the gross violator of human rights," the report said.
As for the military parade in Pyongyang, the State Department expressed regret it has been rescheduled so close to the Olympic opening ceremony, but shrugged it off.
"While we'd prefer this parade not occur on Feb. 8, it is our hope, and I know the hope of South Korea, that the North Koreans who agreed to send people to the games to participate will join with all nations of the world in celebrating the athletes," said Steve Goldstein, the undersecretary for public diplomacy.
Carol Morello contributed from Washington