PRAGUE: Barack Obama met Russian President Dmitry Medvedev in Prague last night to sign a landmark nuclear disarmament treaty that slashes their nations' atomic arsenals. The two heads of state were expected to sign a successor to the 1991 Strategic Arms Reduction Treaty a year after the US President called for a nuclear-free world in a keynote speech. The new treaty, which must be ratified by the US Senate and Russia's parliament to take effect, also imposes limits on the intercontinental ballistic missiles needed to deliver the warheads. The White House hopes the treaty will help yield warmer relations with...