The letter Friday from Gen. Martin E. Dempsey to Sen. Carl Levin, D-Mich., cited the experience of the United States in Iraq and Afghanistan and detailed the effort needed to overthrow the government of Syrian President Bashar Assad. Mr. Dempsey said hundreds of U.S. aircraft, ships and submarines would be used by thousands of American troops to make airstrikes, launch missiles, maintain no-fly zones and train Syria’s opposition forces. He said training alone would cost $500 million a year. Air action would cost $1 billion a month.
Mr. Dempsey said that such action would be “an act of war,” which would entail risks to Jordan, a neighboring U.S. ally, and could backfire in terms of overall U.S. policy.