Exactly the reason(s) no one is proposing eliminating our military. The notion of protecting our people and assets has been hashed out already. There is still a need for that, its just a matter of finding a sane and sustainable level.
When it comes to humanitarian efforts and working to thwart groups, like ISIS, who don't seem to operate with the same moral compass as the rest of us it would be nice to see the US as part of a larger force. Part of it, rather than the de facto leader and provider of the force who may or may not receive additional support from the rest of the world. The UN is a good idea, its just not operated very sensibly and is too disproportionate to be valuable to most of the world. Plus the forces tend to be heavily skewed with US troops or we simply send troops to areas in addition to UN forces. If that changed the US could still play a part in stopping genocide and other atrocities around the world, just as a supporting player rather than the constant point man and there could be more leadership from the areas that are most effected.