So he's not Jimmy Carter after all. Barack Obama was in Prague this week to sign a strategic arms treaty with Russia's Dmitry Medvedev. Next week the US president plays host to 50 world leaders to discuss strengthening arrangements for nuclear security. In between times, he published a new military strategy that significantly narrows the circumstances in which the US would use its nuclear arsenal.

Mr Obama, in other words, looks like a leader pretty much in command of his agenda. These three events mark an important way station on a route he mapped during a speech in the Czech capital a year ago. We are still light years away from the nuclear-free world he mentioned then. But we have stopped heading in the wrong direction. The latest initiatives have restored momentum to multilateral arms reduction. The collapse of the Nuclear Non-Proliferation Treaty does not look quite so inevitable.

This takes Mr Obama some distance from the commonplace caricatures of only a couple of months ago. Then, even sympathetic observers were drawing baleful comparisons with the foreign policy calamities of Mr Carter's presidency. Mr Obama, the argument ran, had spent his first year making speeches about restoring American prestige. He looked destined to spend his second explaining why he had failed.