Historian Eric Hobsbaum famously talked about "the Short 20th Century": 1914 to 1989. The idea being that 1900-1914 was pretty much like the 19th century, but everything really changed with the outbreak of World War 1. Only the fall of the Berlin Wall brought that era, broadly speaking an era defined by wars or the threat of wars in Europe, to an end.
I'm going to make a rash prediction now and say that the first decade of this century started on 9/11/2001, and it ended yesterday, 2/11/2011.
That it started on 9/11 is fairly obvious. Saying that the 9/11 era ended yesterday is why this is a possibly rash prediction, but I think it's fair to say that the game has just changed completely.
For the past decade the main story in world politics has been Islamic extremism. Of course Islamic extremism has not suddenly disappeared overnight; but the way in which the rest of the world deals with it will from now on have to be very different.
For the past 10 years, the people of Muslim countries have had very little say in the matter. Their governments - with just a couple of exceptions - were not democratic. More importantly, they were apparently safe and secure in being non-democratic.
Someone could overthrow them and install newgovernments from outside, but they had efficient internal security and there was no prospect of them being overthrown from within. So to all intents and purposes, our relationship with "the Islamic world" was our relationship with their governments. Get the governments on our side, or not, and the rest will follow, or not. We thought.
That worked, or seemed to, for 10 years. Never again. For better or worse, the people of Muslim countries are now an issue.