THE former Cold War rivals are on the warpath again. The bone of contention: nuclear programmes. When the US Congress recently caused an uproar over Russia's purchase of five American super-computers last year to be allegedly used for simulating nuclear tests, Moscow cried foul. The US government, which is investigating the deal, has blocked the shipment of two of the computers. It alleges that Russia bought the supercomputers—four from California-based Silicon Graphics and one from IBM—bypassing US export controls.