International terrorism by it's definition is going to be restricted to those with the means to travel, and therefore self-select for wealth and/or education. Domestic terrorism however is open to the poor, and I suspect among the Palestinian suicide bombers in Israel you'll find more poor than wealthy.
However, for the US with our small Muslim population, the risk from International terrorism seems much greater to me.
Small? 10 million Muslims is a "small" population? Granted, I doubt even half of them are serious Muslims. (Muslim in name only) and of the remaining number, only a tenth serious enough to become a "Shaheed". (that's 500,000 potential walking bombs) That leaves 4.5 million willing to support and contribute cash to a group or individuals jihad mission. That to me is a fairly large internal threat. Policable? Lets hope so, because that is how we are dealing with it. If we can only prevent more from flooding in, that would be good. Dealing with terrorism somewhere else in the world is preferable.