Why was the american military effort generally unsuccessful, especially the numerous attempt to invade canada?

the circumstances that justified roosevelt´s faith in george curry´s honesty, courage and loyalty were that he served under roosevelt´s rough riders during the spanish-american war and fought in the philippines.   in 1904 theodore roosevelt asked curry to accept an appointment as governor of isabela province (philippines); afterwards served in samar province(philippines) and upon returning to the united states he baecame governor of new mexico territory.