The thing I don't understand about the subsidization argument is that it suggests Europe would choose to spend what America is spending, if America wasn't doing

The thing I don't understand about the subsidization argument is that it suggests Europe would choose to spend what America is spending, if America wasn't doing so already. I think Europe has fundamentally different ideas about the cost/benefit of investment in military. If the US went all-in on isolationism and drastically cut back military spending, Europe likely wouldn't replace American spending dollar-for-dollar. Instead they would spend more on other things, such as health care.