AT LAST Barack Obama seems to be starting to make up his mind. After months of agonising, he is apparently close to announcing that he will after all send a decent number of American reinforcements to Afghanistan. Meanwhile, having barely mentioned climate change since his inauguration, he has now told the world that he is going to the international summit in Copenhagen-and with a provisional promise that the world's greatest polluter will cut emissions.Bold stuff. But both Afghanistan and Copenhagen can also be cited as evidence of a weakness that runs through his foreign policy.