There are five conflicts under "present", none of which are offensive. Two are helping countries put down insurgencies, two are fighting piracy from Somalia and two are involved in civil wars in the Middle East. (They add up to six because insurgents and pirates are allies). Most of them are as part of a giant collation. Only the Syrian one is actually being led by the US.
None of them are to conquer territory or any other description of "offensive war" I've ever seen.
None of them are terribly US specific. The UK is involved in all the same conflicts. France, all but the intervention in Somalia. Three of them have countries like Belgium and Canada involved.
The two fighting pirates who are attacking US ships overseas are clearly "defending the US" under international and US law. (And the coalition there includes Russia and North Korea fighting on the US side). The others are the US honoring it's treaty obligations by defending her allies or honoring the request of a government for help, usually by providing training and logistics support.
Except for Syria, where the US is actually leading a coalition. But that is more a humanitarian intervention than anything else.
