He said any discussion with the Iraqi government to keep a force here next year "has to be done in conjunction with control of Iran in that regard".
But, to keep a force of 60,000 in the field for a year, an even bigger number of men and women ideally about 200,000 and a marked improvement in quality would be needed.
Mrs. Clinton and Leon E. Panetta, who succeeded Mr. Gates as the defense secretary, argued that talks should continue and that the goal, as before, should be to keep a force of up to 10,000.
The United States has a major air base at Incirlik in Turkey, where it carries out attacks on the Islamic State and keeps a force of drones and about 50 nuclear weapons.
Earlier in the week, when details of Obama's official Iraq plan began to emerge, expressions of surprise poured from the offices of the congressional Democratic leadership over his intention to keep a force of 35,000 to 50,000 troops in the country beyond 2010.
Hesse had anticipated some kind of attack from the rear and had kept a mobile force in reserve to guard against such an eventuality.
To counter this threat, the Allies were forced to keep a powerful force of warships with the British Home Fleet, and capital ships accompanied most convoys part of the way to the Soviet Union.
Neither did an agreement that would have kept a small American force in Iraq to train the Iraqi military and patrol the country's skies.
Somehow, these politicians argue, the United States should have just kept a small U.S. force in Iraq despite the opposition, and likely hostility, of the host government.
In a study of Smith, Gosselin, and Houde (2002), participants kept a constant normal force in a search task.
