Orderkaos,
Fair point, but consider another perspective. A major critique of US foreign policy was that they invaded Iraq in 2003 on the pretext that they possessed wmd's that were never found and largely withdrew from Afghanistan before governance was restored.  If the US withdraws from the Middle East now, one could reasonably point out that the US is largely responsible for the mess the Middle East is currently in, and now the US is unwilling to help clean it up.  That's about as irresponsible as a great power can and would seriously disrupt the international order.