Next week’s summit in Moscow between Barack Obama and Dmitry Medvedev is being billed in Russia as the media event of the year, on a par with the great occasions when Ronald Reagan met Mikhail Gorbachev to end the cold war.

The US and Russian presidents are set to agree a new round of nuclear disarmament, cutting the number of missiles they keep from about 5,000 apiece to a mere 1,500. That is quite enough to blow most of humanity off the planet, but the numbers look impressive.