Did economic or social reasons do more to drive America to become much more agressive in foreign policy in the 1890s?
Economic reasons were definitely more important as a driving force behind America’s foreign policy during this time. Sicne you tagged this with “Hawaii,” let me address this in terms of US actions there.
The US had economic interests in Hawaii. The Hawaiian sugar plantations were an important source of that commodity. The people who owned the plantations were Americans. They were the ones who helped, for example, to overthrow Queen Lili’uokalani and to create a republic when the US refused to annex Hawaii. There was some talk that this was motivated by social concerns. The Americans did argue that they were trying to overthrow a monarchy in order to replace it with a better system of government. However, it is very hard to believe that this was a more important reason than economics.
The example of Hawaii (along with that of places like the Philippines) shows that economic issues were a more important driver of US policy than social concerns.