Richard Haas, in India Today:
A third approach to withdrawals can best be described as conditional. Under such an approach, the US would inform the Iraqi government – ideally, following intense consultations – that US troops will be removed unless the Iraqis demonstrate that they are able and willing to meet certain tests or standards by a specified date. Such standards could be military, i.e., achieve a certain level of proficiency, or political, i.e., gain broad agreement on new power- and revenue-sharing arrangements. Most likely, they would need to be both.
This third, conditional-withdrawal approach is another way of casting the first two approaches. If the Iraqis meet the tests in time, then this form of withdrawal resembles the existing performance-based strategy. However, if the Iraqis fail to meet the tests, then the withdrawal would take place after the deadline had passed. It thus would come to resemble in practice a calendar-based exit strategy, with the important difference that a substantial share of the onus for the policy change would ostensibly be on the Iraqis for their shortcomings rather than on the US stemming from a lack of resolve.
This last option of conditional withdrawal is hardly ideal, but it is the least bad course available to the US. This is a time for realism, not ambition.