Did you catch the piece on Turkey tonight on FoxNews? They gave a very interesting explanation for Turkey's failure to allow our troops access. It seems that the Turk army raised the objection to the deployment. Their army admin raised a huge objection that the number of troops we wanted to deploy (70,000 was the number used during the piece). They felt that number was too large for just a move on Iraq from the north and that they thought we were really going to use Turkey as a staging base for an invasion of Syria. So they screamed at the the government and the government went along with the objection. As the Turk government official put it, '6 billion or 60 billion in aid wouldn't make up for 7-8 years of having their region in flames.'
Today, the Turk army officials gave word that they underestimated the strength of Iraq's resistance and now see the need for the deployment, i.e., they were wrong and they're sorry.
It may be a cya story but it could be the reason they said no.