So much of America's power comes from its size: it is one the largest countries on Earth by population and area, and is rich in natural resources and human capital. It is also in many ways an island nation; because it faces no major threats on its borders, it is freer to project power globally.
The allies were prepared to make Germans pay heavily for the damage they had caused, especially in France
Although this depends slightly on what period you're referring to during this time, the best answer would be that "Immigrants" made up the largest percentage of workers in American industry during the late nineteenth century, since the economy had shifted towards industrial output as opposed to agrarian output.
The treaty of Versailles blamed the Germans for causing the war, even though it was the Austrians who started the war. The answer is that the allied powers blamed The Empire of Germany.
He became President at the end of the Reconstruction Era of the United States through a complex Compromise of 1877.
