The Diplomad has a post well up to their usual standard about Turkey's planned accession to the EU which has a lot of discussion based on this:
Allowing Turkey into the EU seems a wise decision for all concerned, in the sense that it sets a good example for the Islamic world. Which makes it interesting that Muammar Qaddafhi described the concept as a Trojan Horse. (Note: We assume this is a reference to Greek mythology and not a brand of condoms, but you never know with Qaddafhi.)
But for all his looniness, Qaddafhi raises a fair point: Entry of Turkey into the EU could potentially bring down the EU. Not necessarily because the EU has to take in 70 million new Muslims, but rather because it has to take in a big, relatively poor country that will place serious economic and political strains on the organization. Anti-Americans out there think that this is probably the reason the United States supported Turkey getting into the EU. They're wrong. The United States supported Turkey getting into the EU for noble, and sensible geopolitical reasons. But if, in the end, Turkey helps bring about the unraveling of the EU, that might not be so bad either.
As one of the many folks who is extremely sceptical of the EU (possibly the logo is a minor hint), I can certainly see the attractiveness of this position. I do however seriously doubt that the EU in the form which its current leaders believe it is in now will survive until 2015 or whenever Tirkey is expected to join. The EU simply has too many problems to last another 10 years without some serious changes. The question of course is whether these changes will be beneficial to either the EU itself or the rest of the world or not.
One obvious possibility, and I regret to say I reckon it is the highest probability, is that the EU simply becomes an enormous corrupt monster- a Soviet Union without nukes and bigger industrial capability if you like. In this sort of scenario the core EU (presumably the original 6 plus or minus) start benefiting rather more than the various peripheral nations and there is always some corrupt horse trading to get the EU to actually do anything. In this sort of case the big change will be that the EU no longer bothers to enforce the free market parts of its treaties and will thus reduce the economic attraction of membership. Whether this just leads to continent wide economic stagnation or something else is unclear, but if it did lead to stagnation why would Turkey want to join?
Secondly it seems not implausible that, because of the various tensions between the statists and the smaller government nations, the EU will start to unravel anyway as the more free-market members (UK, Ireland, Denmark, parts of Eastern Europe?) would quit. In this case it could well be that Turkey would want to join the other peripheral nations who have free trade, some common standards and reciproctiy arrangements but not the political deadweight of the "true EU".
Another possibility is that the Eastern Europeans, probably in conjunction with the UK (though not under A Blair) and some of the other northerly nations, really push for reform of the more egregious aspects of the EU. Things like the CAP and CFP, getting the EU accounts into an auditable state and the like. In which case the EU remains extremely interesting to Turkey, but in such a case many of the reasons to hope that Turkey would cause the EU to unravel would no longer apply.
American SF author Tom Kratman (author of A State of Disobedience) suggests that, Turkey or not, in a few decades the EU will simply become a second Caliphate as the combination of leftist political correctness, islamic fundamentalism and the differences in the growth of immigrant vs "native" european populations leads to the political establishment being taken over. I think this is overly pessimistic but I do think that it is highly likely that over the next decade the tensions between unassimilated Islamic immigrants and their host nations will seriously change the politics of these nations and thus the EU as a whole. Depending on how this plays out it could well turn out that Turkey would actually refuse to join the EU because it would see itself joining an entity that is inimical to the religion of most Turks.
Of course in a decade Iraq could be a stable democracy as could some of the other neighbours of Turkey. In that case Turkey might be more interesting in joining a new middle eastern union where it would probably be the dominant member rather than the EU.