The western allies are in a fine Libyan pickle. The real mission of the British and French military “advisers” being dispatched to the rebel camp is to explore what the west might do to get out of it. The declared objectives of the national leaderships are much larger than the means available to achieve them. It was because defence chiefs on both sides of the Atlantic foresaw this that they were reluctant to intervene in the first place.

David Cameron, British prime minister, was much influenced in his decision to lead a charge against Muammer Gaddafi by memories of alleged western pusillanimity in Bosnia in the 1990s. Thousands of civilians died while the European powers flinched from action without US participation, which Bill Clinton, then president, was slow to sanction.

But military chiefs asked good questions about Bosnia, which went far to explain their hesitation then and justify their successors’ caution now. What are our objectives? Are they achievable? Mr Cameron and Nicolas Sarkozy, French president, with the reluctant and qualified backing of Barack Obama, US president, have supported the weaker faction in a civil war without knowing who the rebels are or whether their cause is sustainable.