foreign policy?

Question

what are the important reasons Americans altered their foreign policy at the end of 19 century to a growing internationalism??

Answer 1

Economics. We needed (and still do) to open up foreign markets for our products. With industrialization, our ability to produce stuff went right through the roof. That necessitated finding more and more people around the world to buy it. Otherwise the factories will shut down as soon as everyone in this country has whatever it is that you are making.
Increased productivity also required going overseas to get more of the raw materials needed to make more of your product. This in turn caused us to get involved in a lot of things internationally that we hadn't had to do previously.

Answer 2

America became an imperialist by invading the Philippines, Mexico, Afghanistan and Iraq.