[lmm]

> The United States has indicated that they would intervene,

The US has made multiple unclear statements. What one president may say, another may walk back or reverse. Or the US might simply not do what they said, or adopt some face-saving half-measure.

Killing US troops stationed in Japan, OTOH, would force a very strong response; even if the government wanted to deescalate, the public wouldn't let them.