これは私も気になったので、エントリで書きました。
2018/05/26 South Korea and Japan will pay for it
https://hyocom.jp/blog/blog.php?key=289051
> During his formal announcement on withdrawing from a planned summit with North Korea, Trump said that both South Korea and Japan “are willing to shoulder much of the cost of any financial burden, any of the costs associated by the United States in operations” if the United States is “forced” to attack North Korea.
>
> Trump then said that he hoped such a step wouldn’t be necessary and that “hopefully positive things will be taking place with respect to the future of North Korea” in the coming months.
何が気になったかというと、この件、日本のマスメディアは伝えていたのか?です。