The other thing about lone wolf terrorists is that it can be hard to draw the line between an act of terrorism, and a crazy person snapping. Was Columbine terrorism? What about some guy that shoots up his office? Does it have to be politically motivated? How do you determine if it is? What if somebody hates the government, but just shoots up their neighborhood mall?
Also, let me predict that the next real terrorist attack in the US is going to be committed not by al Qaeda or Muslims, but by one of those right-wing anti-government second amendment nutjob groups like the one they just arrested in Michigan. Anybody remember Timothy McVeigh? Terrorists don't have to speak Arabic or pray towards Mecca...
Also, that Michigan group shares another feature in common with the Muslim Brotherhood (the Egyptian group that eventually gave birth to al-Qaeda). The Muslim Bros thought by killing the leader of Egypt, they'd spark a simmering cauldron of populist anger which would result in a nationwide uprising against the corrupt, westernized dictatorial government. It didn't work, partly because there was no such cauldron, or it was orders of magnitude smaller than they thought. This Michigan outfit was apparently hoping to do the same thing.