Fewer than one in three of today's members of the United States House of Representatives were in Congress in 2002 for the vote that authorised President George W Bush to go to war in Iraq. The memory of that vote hung heavily over them this week, however, when they approved President Barack Obama's plan to train and arm Syrian rebels to fight the militant Islamic State, also known as Isis. Forty per cent of House Democrats opposed the president's plan but most Republicans backed it, although many complained that his response to the Isis threat was insufficiently robust.
Mr Obama insists that US forces will not engage in a ground war in Iraq or Syria but will only be deployed in support of Iraqi and Kurdish forces and Syrian rebels. His top military officer, Gen Martin Dempsey, appeared to contradict this pledge on Tuesday, telling a Senate committee that US soldiers could join Iraqi troops in attacking some Isis targets. The mixed messages have added to a sense of confusion surrounding the US strategy against Isis and its role in a broad coalition of states that have declared their intention to join the fight. The Syrian rebels Mr Obama wants to arm and train have proved to be ineffective in the past, leaving Isis and other jihadi groups to take the lead in fighting Syria's President Bashar al-Assad. Meanwhile, the new government in Baghdad, although less overtly sectarian than that of Nouri al-Maliki, has done little to address the alienation of Iraq's Sunni minority which helps to sustain Isis.
Turkey, which has an 800-mile border with Syria and Iraq, is confining itself to an invisible role in the fight against Isis, which is holding dozens of Turkish hostages. And Washington is unwilling to co-operate – openly, at least – with Iran and Syria, two of the most effective forces opposed to the jihadi fighters. Mr Obama's confused response to the threat from Isis has helped to turn the US public against him on the one issue he remained popular on; the fight against terrorism.