The specific language from the CoC reads:

"In the event a Passenger misses an onward connecting flight on which space is reserved
because the Delivering Carrier did not operate its flight due to a Schedule Irregularity or Change in Schedule, the Delivering Carrier is responsible to arrange for carriage of Passenger or to make a refund."

Of course, if your ex-Turkey carrier was shut down by the gov't for a few days, I'm sure that carrier would claim Force Majeure.

As far as 9/11, or the start of Iraq fighting (or the blackout, for that matter), you've gotta view these things independently. If it affects 100,000 CO customers, they're much more likely to make a policy change than if it affects 100. Also, since the US airlines are all pretty much sheep, you probably won't see any extend special accomodation by themselves - they move with the crowd.

I'm surprised they won't just dump you on the next flight with a coach seat, though.