North Korea showed off a new submarine-launched ballistic missile and other state-of-the-art weapons during a military parade in Pyongyang last week. The parade followed the conclusion of the latest congress of the North’s ruling Workers’ Party, at which the communist state’s leader, Kim Jong-un, pledged to bolster its nuclear arsenal.

Photos and recorded footage released by the North’s state-run media showed the SLBMs displayed during Thursday’s parade tipped with larger warheads than those unveiled during a previous parade in October.

This time, however, Pyongyang stopped short of displaying its intercontinental ballistic missiles.

The North appears to be upping the ante in a measured manner ahead of Joe Biden’s inauguration as US president this week, while waiting to see what concrete steps the incoming US administration takes toward the recalcitrant regime.

Biden has called for principled diplomacy in dealing with the North. This approach suggests it will be harder for Pyongyang to be recognized as a nuclear-armed state by making concessions short of full denuclearization in return for a significant lifting of US-led international sanctions on the impoverished country.

Nuclear talks have remained stalled since a summit between Kim and US President Donald Trump ended with no deal in Hanoi in 2019, after they failed to find common ground on how to match Pyongyang’s denuclearization steps with sanctions relief from Washington.

During the party congress, the eighth of its kind, Kim defined the US as “our foremost principal enemy,” pledging to “answer force with force.”

He rolled out a series of goals to reinforce the North’s nuclear arsenal, including an improvement in the strike capabilities of missiles targeting objects in the range of 15,000 kilometers, apparently intended to be capable of reaching the US mainland.

The North also boasted of a planned nuclear-powered submarine, saying it has completed the research design. If it launches a nuclear-powered submarine equipped with new SLBMs, its strategic threat to the US will have risen to a more serious level.

It should be noted that, except for the new SLBMs, all other weapons rolling through the central square in Pyongyang last week are designed to mainly hit targets in South Korea.

Among them is a new short-range ballistic missile, believed to be an upgraded version of its KN-23 missile, which resembles Russia’s Iskander. Rather than following a parabolic trajectory, the missile takes a more complicated path, doing a pull-up maneuver over the course of its flight. It is also believed to be capable of being tipped with nuclear warheads, as Kim’s report to the party congress mentioned the advancement in making nuclear arms “smaller, lighter and tactical.”

Experts express concern that it would be practically impossible for the existing anti-missile shield deployed by the South Korean military and US forces stationed here to defend against the North’s simultaneous firing of the missiles and super-large multiple rocket launchers.

South Korea and the US now need to be more closely attuned to cope with the enhanced nuclear threats from the North.

What is worrisome is that South Korean President Moon Jae-in’s administration remains passive, in contrast to the heightened alarm from Washington. Concerns are rising that Seoul’s military preparedness has slackened amid Pyongyang’s demonstrations of its upgraded weaponry.

The Defense Ministry last week decided to delay regular training for reserve forces to the second half of this year due to the coronavirus pandemic. In 2020, it called off the training for the first time since the country’s reserve forces system was introduced in 1968.

South Korea seems to be considering canceling or scaling down an annual joint military drill with the US, scheduled for March.

It is not participating in a US-led multinational anti-submarine exercise that has been underway since Jan. 13 in waters near the Pacific island of Guam. The South Korean military again cited concerns about the spread of the coronavirus as a reason for missing out on an opportunity to improve its anti-submarine capabilities.

Seoul’s reluctance to take actions needed to tighten its military posture apparently stems from the Moon government’s wish not to anger Pyongyang so that it can push for its peace agenda for the peninsula. Moon and his aides should not let their blind pursuit of inter-Korean reconciliation weaken the key alliance with the US and undermine the allies’ defense capabilities against the North’s ever-evolving nuclear weapons.