ON MAY 21st, after a nail-biting session of late-night brinkmanship, China and Russiasigned an enormous gas deal worth, at a guess, around $400 billion. Their agreement calls for Russia’s government-controlled Gazprom to supply state-owned China NationalPetroleum Corporation with up to 38 billion cubic metres of gas a year between 2018 and 2048. The deal capped a two-day visit to China by the Russian president, Vladimir Putin, that included a regional-security summit and joint military exercises off the Chinese coast.

Mr Putin called the deal the biggest in the history of Russia’s gas industry. But it counts, too, for the geopolitics that underpin it. That an agreement should come now, after a decade of haggling, is no accident. The deal will help the Kremlin reduce Russia’s reliance on gas exports to Europe. It is proof that Mr Putin has allies when he seeks to blunt Western sanctions over Ukraine. Both Russia and China want to assert themselves as regional powers. Both have increasingly strained relations with America, which they accuse of holding them back. Just over 40 years ago Richard Nixon and Henry Kissinger persuaded China to turn against the Soviet Union and ally with America. Does today’s collaboration between Russia and China amount to a renewal of the alliance against America?