The American Government was now a bit embarrassed. Domestic public opinion forced the American Government to take the assassination of Roosevelt seriously, but the British's tough stance made the Americans hesitate.
If there really were others behind this incident, then the conflict between the UK and US seemed somewhat unnecessary.
What's more important is that, up to now, it's the Americans who have been bearing the brunt of the conflict losses, as the British Empire controlled the World Alliance and could easily marshal some resources.
However, being in North America, the United States found it exceedingly difficult to obtain some raw materials after European countries successively raised tariffs.
If those influenza compensations were added on, it would make the American finances even worse, and would bankrupt the infrastructure projects that President Coolidge had just begun planning, modeled after those in Australasia.