Regarding the notion that the US is exhausted from wars and has no interest in engaging in military action abroad; do not confuse the sentiments of the people with the plans of the government. The two things are unrelated. Certainly the population has no interest in wars, they almost never do support military action abroad, and their opinion almost never matters. The American public has not influenced military policy since the Vietnam War.
Total American casualties in Iraq were only about 8% of their casualties in Vietnam, and casualties in Afghanistan were even less. Despite the over-dramatization in the media, these were comparatively minor military engagements for the United States. Military funding in America is higher than the spending of the next 10 largest military budgets in the world combined. The point is, war is a fundamental American policy, not a last resort.
The reality is that there has not been a single decade in the history of the United States during which it was not at war. From 1776 until today, military aggression has been a constant feature of America. To suppose that the US is tired of war is to say it is tired of being America. They do not fight because they are threatened, they fight for domination, and they are certainly not tired of dominating.