How does McCain respond to this?
My bet is that he does the only thing he can – ignore it, until he cannot ignore it any longer.
He cannot insist on keeping American troops in Iraq if the Iraqi government is demanding they be withdrawn. He cannot insist on an open-ended commitment to Iraq if the Iraqi government refuses to sign any agreement that would allow American to remain troops in Iraq. Or at least he cannot do either of these without explicitly demonstrating that America is acting as an empire in Iraq, rather than as a partner.
Barack Obama, in the meantime, can point to the fact that he is willing to adjust his position to account for a change in circumstances – and allow the Iraqis to set a date for the withdrawal of American troops. Neither Bush nor McCain can very well insist we are creating a democracy in Iraq if they also refuse to accept the demands of the democratically elected Iraqi government.
This is a good development for Barack Obama politically.
More important, it is a good sign for Iraq itself. Presumably, if the Iraqi government is insisting on this, they do not anticipate chaos to accompany an American withdrawal. Also – it is about time that they began to assert their sovereignty.