The Muslim world is the major ideological holdout against democracy.
To be sure, there are still a few "Communist" states that justify one-party rule with a veneer of ideology. Yet nearly all of them have become market capitalist states in fact. I think it is only a matter of time - short time - before the middle classes being created by capitalism in those places demand a say in the government.
There are also military dictatorships and naked kleptocracies. This will always be true, I think - sometimes gangs get into power.
And there will always be organized criminal gangs in the poorest places, fighting with the legitimate authorities for control.
But since the end of the Cold War there has been only one large bloc of states that ideologically resist, if not reject, the idea of democracy - the Muslim states from Morocco to Indonesia. Turkey has been a Muslim nation with a democratic state for a long time, but it did so at the cost of a fierce secularism. Several Muslim nations have had elections, but they have had a very hard time holding two free elections on schedule, in a row.
Yet it is clear to me that there is a large core of pro-democracy Muslims in every Muslim nation, concentrated in the sectors that are connected to the world economy. If the wave of pro-democracy movements sweeping the Muslim world right now were to bear fruit in several states at once, the back would be broken of Islamic ideological resistance to democracy.
If the Muslim world became predominantly democratic, there is not now another serious anti-democratic ideology capable of creating a bloc of states. There would still be islands of tyranny, and there would still be plenty for democratic states to argue about, both internally and with each other. But we can imagine a world, within this generation, of democratic states.