The US could? The US has used soft/hard influence for a long time. We've crop dusted Colombian fields attempting to eradicate cocaine. We've eliminated leaders in Central and South America. We've influenced elections trying to get specific leaders elected. We've sanctioned the shit out of one little island, we blockaded the island when it was allowing itself to be used/influenced by another government we didn't like. We've allowed US corps to invest and build infrastructure within these countries. We've given them millions/billions in various ways including straight cash injections.

I don't know how much more would need to be done for you to think things are being done.