It could've happened here. Or anywhere for that matter. They have all the opportunities. We only have to make one mistake.
True, it could've happened here (i.e. the USA), but I now think our security and intelligence is probably among the best in the world post 9/11. We have no choice.
Any theories that maybe the Irish Republican Army (the IRA) was behind this with the help of Al-qaeda? After all, although they may have different goals their agendas might dovetail at times. As the old saying goes "the enemy of my enemy is my friend."