Related to the posts above, and certainly a topic worthy of debate is President Obama's retrenchment

The Strategy of Retrenchment and Its Consequences

http://www.fpri.org/articles/2015/04...s-consequences

Over the past decade or more, leading academic foreign policy realists have argued for US strategic retrenchment. Retrenchment is a strategy designed to reduce a country's international and military costs and commitments.[1] This can be done by cutting defense spending, withdrawing from certain alliance obligations, scaling back on deployments abroad, or reducing international expenditures. Retrenchment does not necessarily involve the avoidance of all strategic commitments. But the desired direction with retrenchment is one of lowered cost and reduced commitment.
Allies depend upon believable, material indicators of American commitment, including a strong military presence together with a credible readiness to use it. Adversaries are deterred by the same. Some leading strategic statements issued by the administration, such as the new National Security Strategy, do not really spell out or concede any such trade-off between cost and risk. Instead, they simply take it for granted that the increased risk is manageable. In effect, current plans assume or perhaps hope that international adversaries will not take advantage of America's scaled-back ability to handle a range of possible challenges. US adversaries may not be so forgiving. They might also misperceive the true extent of American commitment and resolve, under the impression the US won't respond. Indeed this is how many of America's wars have begun in the past.