In the boldest act of escalation to this point, Syrian defense forces shot down a Turkish warplane that flew into Syrian airspace this morning, prompting Turkish authorities to call an "emergency security meeting," as both pilots of the F-4 Phantom were rescued successfully.
There are conflicting reports over what exactly occurred, but there seems to be one common story line: at some point this morning the Turkish F-4 Phantom was shot down near Syrian airspace; Syria apologized; both countries worked together to retrieve the pilots and Turkish authorities are meeting over the event.
With the crisis in Syria reaching critical mass, and now the nation's defense forces intentionally targeting foreign warplanes (we know this as fact, as Syria has grounded most of their air force after yesterday's defection), the time and place for a serious discussion over military intervention has been reached.
Specifically Article 5 of the Washington Treaty, which states that an "armed attack against one or more of them in Europe, or North America shall be considered an attack against them all." If Turkey feels that it was deliberate and constitutes an act of war, they can invoke Article 5 and NATO would be at war.
Stay tuned to the Middle East... Things could get interesting very quickly.