Answer: I wouldn't say that it was the American Military and their global presence that caused it. It was more or less the new American Ideology that caused this. At the time the American Navy was slim, but still more powerful than the Spanish, the army was more than fit to deal with most battles at the time due to the over-fighting they have done since the creation of the country. If you really want to see how the military caused this then think of the power balance in the area at the time. The Spanish were having the same issue's the British had during the American Revolution, also the Americans were basically fighting on/off their own homeland
Step-by-step explanation:
What we see today inside of the world is that almost every country inside of the world can get their military anywhere within a few days to at most a week. Although this is nice back when sails and basic fuel or steamships were going around it could take up to 2 Months (if it could even make it there without sinking). Not to forget that the United States Army was one of the most advanced in the world!