Entering 2007, President George W. Bush possesses all of the powers that Article II of the U.S. Constitution grants the president. But Mr. Bush is now finding out that there are new limits on his authority, a sharp change from the wide-ranging freedom of action he previously enjoyed. As much as he wants to reinforce the American strategy in Iraq boldly, the new restraints on his authority will likely cause Mr. Bush's new plan for Iraq to be more of a tepid rehash. After it becomes clear that the White House and Pentagon's exhaustive policy review has produced a plan than is neither imaginative nor effective, Mr. Bush will then likely lose control over Iraq policy to an energized Congress, just as happened with respect to the Vietnam conflict between 1973 and 1975.

President Bush and his advisors seem committed to the current strategy of political reconciliation, institution-building, reconstruction, and counterinsurgency in Iraq. A recent report from the Washington Times explains how few new ideas have emerged from the long policy review. Mr. Bush and his advisors are trying to re-energize the current strategy. But the news reports about the Bush administration's strategy review show harsh constraints binding President Bush and his administration.

A recent article from the New York Times discussed the practicalities of the troop "surge" option. In order to boost U.S. troop levels by 17,000 to 20,000, Pentagon planners are considering extending the deployment of two Marine regiments in Anbar province past their current February departure date. In addition, planners may move forward the deployment of several Army brigades already slated to arrive in Iraq next spring. Such tinkering with long-set deployment schedules will only yield a few months' boost in troop levels, during which time enemy insurgents and militias can easily hide from temporarily increased American patrols.

The schedule-fiddling suggested in the New York Times and Washington Times is far away from the 30,000 soldier, 18-month commitment recommended by General Jack Keane, USA (ret.) and Mr. Frederick W. Kagan, the leading proponents of the "surge" strategy. Although it remains to be seen what exactly Mr. Bush will propose, it seems unlikely that the President will be able to implement the Keane/Kagan recommendation.

Although General Keane and Mr. Kagan argue otherwise, U.S. ground forces are in no position to add 30,000 troops to Iraq for 18 months. The current rotation policy is already depriving U.S. Army and Marine Corps units of necessary home station time for retraining and unit cohesion building. The Joint Chiefs of Staff have openly expressed their objections to the surge option. General Peter Schoomaker, the Army Chief of Staff, has warned that the active-duty Army will soon "break" and that he has told the President that he opposes a surge to Iraq. General James Conway, the Commandant of the Marine Corps, has expressed the same reservations. If President Bush ordered a "surge" deployment to Iraq that the Joint Chiefs or other senior generals considered both harmful and unproductive, it is certainly possible that there could be dramatic resignations among the Chiefs or other senior flag officers. General Schoomaker himself would be a prime candidate for this act - he reluctantly came out of retirement at Secretary Rumsfeld's urging, has served a full tour in his current billet, and has nothing more to prove.

President Bush must also consider Congress and its appropriation powers in Article I of the Constitution. At a minimum, large minorities and perhaps slim majorities currently exist in Congress opposing the "surge" option. We can be certain that one of the first acts of the new Democratic committee chairmen will be to hold hearings on Iraq policy, hearing that will get eager coverage from the media. The Joint Chiefs will be perhaps the first panel to testify, and Senators will ask the generals to repeat their concerns about the "surge" option and the negative effect it would have on military readiness, contingency planning, and strategic risk. After the generals deliver that testimony, it would then be safe for Republican members to side with the military and oppose the President, should the President want something resembling the risky Keane/Kagan plan. It would then be a simple matter for Congress to impose, through the appropriations process, a cap on the number of American troops permitted in Iraq.

The President originally hoped to reveal a new policy for Iraq earlier in December. This was postponed to after Christmas, then into early January. Each day Mr. Bush is finding new political constraints, previously unfamiliar, now tightening around him. These constraints will force his new policy to be both a disappointment to nearly everyone and ineffective.

It will also be the last attempt at Iraq history will offer to Mr. Bush. After that, for better or for worse, committee chairman on Capitol Hill will likely determine America's strategy in Iraq.

The author was a U.S. Marine Corps infantry company commander and staff officer. He was the global research director for a large private investment firm and is now a private investor. His blog is Westhawk.