Russia’s ruble may have crashed, but it hasn’t lost its chess skills. The Kremlin is working to oust the US from a vital air base in the Central Asian republic of Kyrgyzstan, complicating the war in Afghanistan; at the same time, it’s planning an international military force to rival NATO. The Kyrgyz base, Russia said, could be used to house part of the planned new force. “These are going to be quite formidable units,” said Russian President Dmitry Medvedev. “According to their combat potential, they must be no weaker than similar forces of the North Atlantic alliance.” It’s Moscow’s most aggressive step since its war with Georgia last summer, and it’s a challenge to Obama’s new administration, which has placed Afghanistan at the top of its foreign policy priorities.