Why American entry in 1915 would not instantly end World War I

Would American entry in 1915 under Theodore Roosevelt end World War I earlier and change participation in the League of Nations and naval treaties?

Equipment and industrial mobilization constrain the earlier-entry scenario, while its League and naval-treaty outcomes remain unresolved.

The 1915 entry scenario turns on the gap between industrial potential and equipment ready for service. An earlier American army could initially draw more heavily on British and French supplies, while useful numbers of destroyers would still take time to reach the war. Factories require tooling, trained workers, components, and transport before they can sustain a mass force. The comparison with World War II emphasizes the production and export work already under way before American entry in 1941. The question also asks about the League of Nations and naval treaties. Clarke's reply questions whether those arrangements would emerge in the same form under the hypothetical Theodore Roosevelt presidency, without establishing a definite alternative settlement.