Granted, the United States has "status of forces agreements" with about 115 countries and most of these SOFAs were created solely by executive actions. The new agreement with Iraq is, however, more consequential than a normal SOFA. Besides, after all the American blood and treasure sunk in Iraq, and after the deep divisions among Americans caused by the way the war was justified and the occupation was conducted, any negotiated arrangement that formalizes ongoing U.S. security commitments or assurances to Iraq should take the form either of a treaty requiring a two-thirds vote of the Senate or a "congressional-executive agreement" requiring simple majorities in both houses of Congress.
As senators, the current president, vice president and secretary of state took their stands on the principle that the legislative and executive branches share foreign policy responsibilities. It is, however, axiomatic that where you stand depends on where you sit, and Obama, Biden and Clinton now sit in the executive branch. So perhaps they will be less inclined to stand on the principle that power should be divided so that important decisions will be debated by rival sources of responsibility. Situational constitutionalism is not new, but if Obama, Biden and Clinton now embrace it they will continue -- and ratify -- the executive branch aggrandizement by the previous administration.
As Democrats, Clinton, Obama and Biden were concerned before the election that President George W. Bush might bind his successor to repugnant policies. There is, however, a larger matter still at issue -- the constitutional balance of executive and legislative responsibilities regarding foreign relations. Even were it certain -- it is not -- that U.S. forces will be out of Iraq on a particular date, that would not drain the constitutional question of its salience.
America, having nurtured constitutional government in Baghdad, should not neglect it here. If Congress is going to rebuild some of the institutional muscle that has atrophied from disuse under majorities of both parties and in relation to presidents of both parties -- if Congress is going to regain responsibilities it forfeited to the executive branch during the Cold War and other undeclared wars -- Congress must debate the new agreement with Iraq. Besides, it would be instructive, and entertaining, to watch many Democrats reluctantly join many contented Republicans in praising an agreement, perhaps modified by this president, to continue a U.S. presence in Iraq of perhaps 50,000 troops, a presence that surely involves "commitments or risks affecting the nation as a whole."