Whether one liked the speech or hated it -- and there are people I respect on both sides -- the obvious conflicts between what the President is saying and doing now, versus what he said and did before becoming President has two effects:
First, it highlights the profundity and depth of his inexperience as he entered The White House. After all, time and events have a way of making the sound-good, feel-good broadsides against George W. Bush's foreign policy significantly more complicated ow that he's the one in charge.
Second, it undermines his "brand." Wasn't he supposed to be the guy who was going to make "the world" love and respect America again? Wasn't he the guy for whom warfare wasn't just appalling -- but unnecessary, given all the "resets" and "open hands" he was going to offer across the world?
So what happened to turn the Obama '08 into the Obama '11? What happened to turn the anti-Iraq war guy into the pro-Libyan-war-without-congressional-authorization guy? Oh, yeah. Life happened. The real world happened. Reality intruded, as it so often does.
Apparently, it's a lot more difficult and complicated when you're actually in charge.