Imagine...
that a country (the "Good Guys") was going to invade another country (the "Bad Guys"). Next door to the Bad Guys lived the Good Guys' ally, the Friends. Say that the Friends had a long-standing, simmering dispute with an ethnic group (oh hell, call them "Kurds") that lived both in Iraq and Turkey. Indeed, say that the Turks had soldiers actually in the Kurds enclave in Northern Iraq just to make sure they didn't get too uppity.

In light of all of the above, wouldn't it be extremely foolish to get involved in a war in Iraq before coming to an agreement with the Turks? I don't know about you, but it scares me to have the Turks and Kurds on edge, while we have American Special Forces in the area. This is one of the ways that war creates it's own reality -- when people start shooting, it's hard to control how others react. It's easy to think of a scenario where Americans and Turks are shooting at each other.