Baghdad ? Iraq’s Cabinet decided Tuesday to ask the U.S. for changes to the draft agreement that would keep American troops here three more years, as key Shiite lawmakers warned the deal stands little chance of approval as it stands.

The decision, reached in a closed-door meeting that lasted nearly six hours, raised doubt that the agreement can be ratified before a new American president is elected next month.

Parliament must approve the draft before the current U.N. mandate expires on Dec. 31 or no legal basis will exist for the U.S.-led military mission.

Such an outcome would force hard decisions in Baghdad and Washington on the future of the unpopular war.

Critics maintain the draft falls short of Iraqi demands for full control of their own country after nearly six years of U.S. occupation. Supporters insist Iraq still needs U.S. military and political support as it builds its security forces and governmental institutions.

Opposition, however, is divided, with different parties objecting to different parts of the agreement, which could make it difficult to win broad support for the entire document before the year-end deadline.

Prime Minister Nouri al-Maliki and his ministers reviewed details of the draft, hammered out in months of tortuous negotiations, and concluded that changes were needed “to raise the agreement to a nationally acceptable level,” government spokesman Ali al-Dabbagh said in a statement.

Cabinet members will prepare a list of proposed changes to present to the Americans, al-Dabbagh said without giving a timeframe.

Government officials said al-Maliki wanted the proposed changes submitted today so the full Cabinet could consider them Sunday.

The officials said the ministers of planning, defense and interior – which rely heavily on U.S. support – agreed to accept the draft without any changes. Others in the 37-member Cabinet raised various objections to the draft.

There was no immediate comment from the U.S. Embassy and no indication whether the U.S. would agree to further changes. Foreign Minister Hoshyar Zebari said last Saturday that it would be difficult to reopen the negotiations.

In Washington, State Department spokesman Sean McCormack said the Bush administration was waiting for a formal statement from the Iraqis before commenting.

The agreement calls for U.S. troops to leave Iraqi cities by the end of June and withdraw from the country by Dec. 31, 2011, unless the government asks them to stay. It would also provide limited Iraqi jurisdiction over U.S. soldiers and contractors accused of major, premeditated crimes committed off post and off duty.