Was america's road to becoming an empire justified

This is a very complex question with no definite answer. The issue is whether America's actions on the gobal level were altruistic or selfish. Has America defended liberty, or enslaved people behind the mask of liberty? We can not state that the  U.S. has never exploited people or that it has always been democratic. In the period of the Cold War, it has supported  anti communist dictators. In certain situations the U.S. has acted as a supreme nation over other nations, which may lead us to believe that in fact it was acting imperialistic. We can also look at it this way: if the U.S. did not act imperialistic, humanity would never evolve to a stage when exploitation of others and promotion of self interest became unwanted and called out. Humanity now  seeks to promote the well being of the whole. America's role in it will be judged by it's attitudes toward that process.

according to classical republican political theory, which democratic republics would function best?

a.   small republics, with people who had similar interests

b.   large republics, with people who had competing interests

c.   republics made up entirely of landowners

d.   republics made up entirely of servants