From Global Guerrillas John Robb writes:
The question for global guerrillas operating in Iraq is: how do you bait Turkey to invade Kurdistan?
Turkey already has 140,000 troops massed on the border with Kurdistan -- in response to its support of PKK guerrilla attacks within Turkish territory. One mechanism is to heat up attacks on ethnic Turkmen living in Iraq (a social systempunkt of 800,000 people). The early July marketplace car bomb in Emerli, which killed an estimated 210 civilians, was a step in this direction. We can expect more attacks like this in the future. A Turkish invasion of Kurdistan would achieve:
* Political disorder. A massive rift between the US and Turkey. A defacto state of war between Iraq and Turkey. Strong alignment of political goals between the PKK and Kurdistan.
* Factional disintegration in Iraq. The departure/desertion of Kurdish troops from the Iraqi army. Refurbished Kurdish peshmerga are the heart and soul of the Iraqi army (as well as many private military companies).
* Supply and economic disruption. Loss of vital commercial connectivity with Turkey (needed for a huge range of business and supply needs).
There is not much more for me to say on this, except that this is within the range of reasonable possibilities and would be a disaster. Turkey is vulnerable to being baited because they are very sensitive about both the Kurdish and Turkmen issue.
And if they came into Kurdish Iraq, they would have quite a fight on their hands vis-a-vis the peshmerga. Just like with US troops, the Turkish army would win the mechanized, conventional war and then end up in an endless grind of guerrilla warfare. Turkey was not really able to subdue the PKK for years in Turkey and the PKK was much weaker than the peshmerga are.
And beyond that, it probably puts all of Iraq in play and makes a US withdrawal all but impossible.
Right now, this is just muscle-flexing by Turkey, but it will be interesting to see what happens. The Kurds, spread across Turkey, Iraq and Iran, remain the largest ethnicity by far without a nation-state and have to secretly be wondering if and how this turmoil ends up giving them an opportunity to carve out a state of their own (a la Kosovo).
Of course the wisest thing for Turkey would be not to take the bait, so we will see if they have that level of strategic maturity on the issue.