William Hague made it clear on the Today programme this morning that he and David Cameron are determined not to rule out the option of arming the Syrian rebels. He challenged those who warn that the UK would have no way of preventing Sunni jihadists from seizing or buying the weapons by pointing out that there was "no evidence" that the non-lethal equipment supplied by the west had "fallen into the wrong hands" and cautioned against "falling into the trap of thinking that everybody on every side is an extremist". He also insisted that while the opposition had suffered "important setbacks", "this does not mean this conflict is over".
"The debate about arms is about how to make sure a democratic, legitimate opposition is not exterminated," he said. The clear suggestion was that supplying the rebels with weapons could still tilt the balance in their favour, both against the extremists on the opposition side and against the Assad regime.
But such is David Cameron's political isolation that it is increasingly imposible to see how the UK could take this step. Labour, the Liberal Democrats and around two-thirds of Tory MPs are all opposed to arming the rebels, and Boris Johnson uses his Telegraph column  today to join them. He writes: "This is not the moment to send more arms. This is the moment for a total ceasefire, an end to the madness. It is time for the US, Russia, the EU, Turkey, Iran, Saudi and all the players to convene an intergovernmental conference to try to halt the carnage."
Last night on Twitter, Tory MPs Mark Reckless and Sarah Wollaston suggested  that they knew of no Conservative backbenchers in favour of arming the rebels. After the adventurism of the neoconservatives, the Tories' realist tendency is reasserting itself. If Cameron is unable to even win this argument within his own party, it is hard to see him persuading anyone else of the case for action.