All politics are local, except for oil politics. The Russians think these low oil prices are an American-Saudi conspiracy. American commentators believe that the Saudis have driven down prices to punish North Dakota s shale oil revolution and drive its high-cost producers out of the game. In Canada, the paranoia in Calgary is that the Saudis and other Gulf oil producers want to drive the oil sands out of business.

Iran signed an agreement with Russia to obtain as many as eight new reactors, as world powers struggle to reach an accord capping the Islamic Republic s nuclear program. The deal was signed in Moscow yesterday by Ali Akbar Salehi, head of Iran s Atomic Energy Organization, and Sergei Kiriyenko, the chief executive of Rosatom Corp.

Obama administration wants Tehran to come to heel over its nuclear programme. It wants Vladimir Putin to back off in eastern Ukraine. But after recent experiences in Iraq and Afghanistan, the White House has no desire to put American boots on the ground. Instead, with the help of its Saudi ally, Washington is trying to drive down the oil price by flooding an already weak market with crude. As the Russians and the Iranians are heavily dependent on oil exports, the assumption is that they will become easier to deal with.

The outline of the deal, which is all that's available, suggests it is a five-year agreement worth up to $20 billion. Russia will provide goods and services to Iran, including food and oil industry expertise. Iran, meanwhile, will get an outlet for its oil. And a big one! Russia appears willing to buy up to half of Iran's oil exports, or roughly a fifth of its total output.

Despite public assurances by Western officials, concern is growing that the escalating animosity between the United States and Russia over the Ukraine crisis could have a corrosive effect on the nuclear talks with Iran. Even before the Obama administration expanded the scope of sanctions on Thursday over Russia s annexation of Ukraine s Crimean Peninsula, the Russians had sent signals that their retaliatory tools might include an altered position regarding the Iran talks, in which Russia and the United States are colleagues in the six-nation group negotiating with the Iranians.