A flurry of newspaper articles reporting that the Obama Administration may decide to disregard the advice of its military commanders and reduce the U.S. military presence in Iraq to less than 4,000 troops by the end of the year prompted 42 distinguished American foreign policy experts to write an open letter to President Obama on September 15, urging him to reconsider.

The letter, published on the website of the Foreign Policy Initiative, stated that the signers were “gravely concerned” about the risks entailed in retaining such a small force:

Failure to leave a significant U.S. military presence in Iraq will leave the country more vulnerable to internal and external threats, thus imperiling the hard-fought gains in security and governance made in recent years at significant cost to the United States. A successful, democratic Iraq will remain a model for other emerging Arab democracies and one day, its neighbor, Iran. However, a failing state in the heart of the Middle East would destabilize the region, empower Iran, and make vain more than eight years of efforts by the United States in Iraq.

Although violence in Iraq is much diminished from its peak in 2004–2007, Iraq’s fragile coalition government needs continued U.S. military assistance to ward off the threats posed by pro-Iranian militias, al-Qaeda in Iraq terrorists, and simmering tensions over territorial disputes in northern Iraq between Iraq’s Kurds, Arabs, Turkmen, and Christian groups.

It has long been clear that the United States needs to remain engaged beyond 2011 in stabilizing one of the Middle East’s most pivotal states. Iraqi and American official are quietly negotiating behind the scenes to extend the presence of U.S. troops past the December 31 deadline set by the 2008 Status of Forces Agreement.

The Obama Administration should now make every effort to avoid squandering the hard-won security gains in Iraq by withdrawing too many troops too fast. Iraq still needs substantial U.S. military, diplomatic, and political support to defeat various insurgent groups, stave off a possible return to civil war, and contain Iran’s expanding influence.