Turkey has made clear that it reserves the right to send troops into northern Iraq, despite heavy pressure from the United States and the European Union to keep out.
Turkish officials say that their primary goal is to prevent a humanitarian disaster - an outflow of refugees from Northern Iraq.
The US would prefer it if no more Turkish troops entered Iraq
That has happened before.
After the last Gulf War almost half a million Iraqis - mostly Kurds - fled to the Turkish border after President Saddam Hussein brutally crushed their uprising.
This time, Turkey says, it will offer humanitarian assistance to displaced Iraqis "inside Iraq on more suitable terrain."
It is also keen to prevent remnants of Turkey's Kurdish separatist group, the PKK, from using a refugee exodus to sneak back into Turkey from bases in Northern Iraq.
All eyes on Kirkuk
But in reality, other factors play more heavily.
Turkey's worst nightmare is that Northern Iraq's three-and-a-half million Kurds will exploit the war to strengthen their position - to move one step closer to an independent Kurdish state.
That, the Turks fear, might encourage their own substantial Kurdish minority to contemplate similar moves.
The Iraqi Kurds have desperately tried to assure Turkey - and other neighbouring countries with Kurdish minorities - that all they want is to remain part of a new, federal Iraq.
But the fact that last year the Iraqi Kurds named the oil-rich city of Kirkuk as the capital of their own future state within a federal Iraq set off alarm bells that are still resonating in Ankara.
Turkey fears that if the Iraqi Kurds were to grab Kirkuk during a war, it would not only give them greater economic and political clout in a post-Saddam Iraq, but would undermine the position of ethnic Turkmen in a post-war settlement.
Turkey has traditionally defended the interests of the Turkmen, who also have a large population in the Kirkuk area.
How all this political manoeuvring might play out - both during the war and afterwards - is still unclear.
The US and the Iraqi Kurds would clearly prefer that Turkey did not enter northern Iraq at all.
But given Ankara's apparent determination to do so, talks may be focusing on specific conditions for any incursion.
The US has told Kurdish militias not to try to seize Kirkuk
Reports suggest that the US has made it clear to the Kurds that their militias must not try to seize Kirkuk.
US demands that Turkey agree to put its forces under coalition command - which have so far been resisted - also appear aimed at ensuring Ankara does not make a rush for the oil-rich city to keep the Kurds out.
Turkey is insisting that it will not "invade" northern Iraq.
It says that if its military does go in, it will do so in co-operation with the US - and that there will be some form of co-ordination with the Iraqi Kurds.
But Washington remains uneasy.
What it fears most is fighting between Turkish forces and the Iraqi Kurds, who are deeply hostile to a Turkish deployment.
Turkey may assume that if it has its own forces on the ground in Iraq, this will increase its influence when it comes to a post-war settlement.
The presence of Turkish troops may help bolster the negotiating position of Iraq's ethnic Turkmen.
Kurds are taking refuge in caves as US aircraft bomb Iraqi positions
Their presence could also deter Iraqi Kurdish groups from even considering trying to take Kirkuk or Mosul, another strategic city in the northern oil zone.
The US and the EU may eventually grudgingly have to accept a limited, short-term, Turkish incursion into Northern Iraq - perhaps setting up the 20-kilometre border "security zone" that Turkey has been talking about.
But if there is fighting between Turks and Iraqi Kurds - or if Ankara does not withdraw quickly after the war - Turkey's plan could backfire.
A large-scale, long-term Turkish military presence in northern Iraq would further aggravate relations with the US, would inflame the Iraqi Kurds and could tempt other regional countries to make their own incursions into Iraqi territory.