The new Secretary of Defense says ties with both Japan and South Korea will be strengthened. The ties with both country’s militaries are already very strong. If anything it will be interesting to see if ties with South Korea degrade if President Trump decides to cancel joint military exercises like he did in his first term when pursuing diplomacy with North Korea:

Defense Secretary Pete Hegseth spoke Friday with his counterparts in South Korea and Japan, vowing to strengthen military ties with both countries amid regional security concerns, according to their respective defense ministries.
In his first phone call with South Korea’s acting defense minister, Hegseth and Kim Seon-ho agreed to “deepen and expand the level and scope” of their 71-year military alliance and strengthen security ties with Japan to deter North Korea, South Korea’s Ministry of National Defense said in a statement Friday. Hegseth also spoke that day with Japanese Defense Minister Gen Nakatani. The two expressed their “firm intent to continue the initiatives to reinforce the alliance,” Japan’s Defense Ministry said in a news release.
They also agreed to “bilaterally cooperate to realize the vision of a free and open” Indo-Pacific and reaffirmed that their security treaty covers the Senkaku Islands, which China claims as its territory.
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