To me, you have to ask a couple of things in order to answer this question.
First, you have to ask whether America is more likely as a country to be invaded and destroyed or weakened in a serious way. I do not think you can argue that we are. There is no serious threat of invasion. Our overseas wars have not made us more likely to be attacked by nuclear weapons.
Second, you have to ask if we are more likely to be killed here in the US as a result of these wars. There is no real evidence that we are. There have not been any successful terrorist attacks within the US that you can really say were caused by our being involved in wars overseas.