From the article:

The impact on the region of a Turkish attack, if it takes place, will depend on the extent of the intervention. If it is confined to the mountains on the frontier, where there are only a few villages, then the KRG would be unlikely to respond. Turkish incursions by 35,000 to 50,000 troops in 1995 and 1997 failed to achieve anything. But if Turkish forces advance into important towns and cities then Kurdish troops would be bound to respond. The KRG will also want to prevent a precedent being established whereby the Turkish army can cross the Turkish-Iraq frontier at will.

Turkey has been alarmed to see the development of an effectively independent Kurdish state in northern Iraq and an Iraqi government in Baghdad in which the Kurds play a leading role. It is particularly anxious about the referendum which might lead to the oil province of Kirkuk joining the KRG under a poll which was promised under the constitution for the end of 2007 but may now be delayed."