Turmoil in the Middle East looked like a gift to the presidential campaign of Mitt Romney. With unseemly eagerness, the Republican candidate unwrapped his present – blaming the Obama administration for encouraging Islamist militancy. Conservative commentators chimed in. On Fox Television, Charles Krauthammer announced: “What we are seeing on the screen is the meltdown, collapse of the Obama policy on the Muslim world.”

With an American ambassador dead and US embassies under assault, this is an easy accusation to make. But it is wrong. Rather than making things worse, the policies pursued by Barack Obama mean that the US is much better positioned to deal with the anti-American violence that has been a feature of politics in the Middle East for decades.

The conservative critique of Mr Obama relies heavily on selective amnesia. The argument seems to be that before his election, the US was strong and respected across the Middle East. But now a weak president has returned America to its enfeebled state under Jimmy Carter, when US diplomats were taken hostage in Iran. That humiliation, the Republicans well remember, contributed mightily to Mr Carter’s 1980 election defeat.