If the United States joined Japan against Russia

What changes if the United States joins Japan against Russia after the Second Pacific Squadron sinks an American ship?

It could make the war nastier, but American forces could not easily intercept the Russians and might not change the decisive outcome.

American forces were poorly positioned to intercept the Second Pacific Squadron during its voyage, so they could either pursue a difficult chase or reinforce Japan. Joining the Japanese fleet would also raise a coalition-command problem: the Americans would have to accept Japanese direction or arrive expecting to lead. More ships could make the campaign harsher and more complicated without changing the decisive geometry of the war. The panel therefore doubts that intervention would necessarily alter the result at Tsushima.