Yet the same UAV have got to be useful to kill the president of the US (I do not have any desire to kill him, but I imagine there are people who do).
So, how the hell do you protect somebody against these kinds of weapons? The bullet-proof glass that is (almost certainly) installed in the oval office is properly enough to stop any kind of sniper bullet, but a missile? Heck the Iranians have anti-ship missiles that can fly at march 2.
How do you stop something like that? I have to guess that the Secret Service have tried, but I doubt it can be done.