Being an American who primarily comments on US politics and public policy I have, over the years, primarily concentrated on the logic for the United States of America to setting a timeline for withdrawal of our forces from Iraq. But with Iraqi Prime Minister Nouri al-Maliki talking up the timetable option it's worth considering that it has a solid logic from an Iraqi point of view.
The Iraqi government, it seems clear, would like some continued support from US combat forces. And the United States, for good reason, doesn't want its forces running around Iraq engaged in combat while being subject to Iraqi law rather than the Uniform Code of Military Justice. At the same time, the Iraqi government wants to be the government of a real sovereign country which is incompatible with a foreign army running around the country engaged in active combat and not subject to Iraqi law. One easy way to thread the needle of continued US combat engagement in Iraq while maintaining a meaningful sense of Iraqi sovereignty is to make the US presence temporary in a definitive way. Which is to say -- setting a timetable for withdrawal. That should buy the United States an added degree of public support within which to conduct some additional operations and leave the best possible situation behind.