I would agree with your comment prior to WWI.  The Phillipines is an example, though per Wikipedia there was opposition,

Nevertheless, many Americans deeply opposed American involvement in the Philippines, leading to the abandonment of attempts to construct a permanent naval base for use as an entry point to the Chinese market. In 1916, Congress guaranteed the independence of the Philippines by 1945.

There were issues with Cuba, which could potentially have a strong blockading potential on key southern ports, like New Orleans.  And there was debate about the "sphere of influence" concept regarding Central and Southern America,,,,,was European influence there acceptable, should it be acceptable to America, was it a threat.  There was a lot for a young country to sort through,,,and the European powers had certainly established a model of colonialism and power through overseas might.  And you are right, the US exercized its power in all of these situations.