My thought is that this is simply a matter of time (and initiative and opportunity).<p>High-level targets, say, top leadership of G8 nations, would likely be difficult. But attacking key field leadership, business executives, or heads of state of smaller nations is well within current capability.<p>A drone buzzed Angela Merkel a couple of years ago (video on YouTube), and a Russian leader more recently.<p>My sense is that a small directed weapon (effectively: gun) would be more effective, though an explosive charge and shrapnel could certainly be utilised.<p>The technological advantage the US and other advanced nations have in drone technology is quite likely to be short-lived. Especially if your interest is, say, 1-5km range, rather than 100-500km.