Foreign policy doesn’t operate mechanically, on autopilot. Its effectiveness is determined entirely by the nature of the national administrations involved. You take the Bush 41 administration, and it can make a particular basic policy — say, in the war on terror — achieve a detectable level of good effect, in spite of the setbacks and “friction” (in the Clausewitzian sense) that are inevitable with international relations.
You take the Obama administration, and officially, it will modify the same basic policy on the edges. But in reality, the Obama administration becomes known for things like zero follow-through, strategic sclerosis, narcissism, unreliability, and desperation for photo ops and a favorable narrative. The same policy, modified, can’t work under those conditions.
This is a good point and should give pause to anyone who is reassured by assertions that the Obama administration’s anti-terror activities are an extension of what the Bush administration did. In fact, Obama’s weakness and ineptitude make it impossible for him to get the results Bush did, even if Obama wants to.
Executive competence is a critical variable in foreign-policy success. There is no adequate workaround for executive incompetence.