If Ukraine is a battle waged with rubles, Russian President Vladimir Putin is mounting another attack. Russia’s ex-KGB leader sent a letter to Ukraine saying the Russian natural gas company, Gazprom, “has issued an advance invoice for gas deliveries to Ukraine, which is completely in accordance with the contract, and after June 1 gas deliveries will be limited to the amount prepaid by the Ukrainian company.” Like the Associated Press reported, Ukraine is the struggling middleman that supplies Europe with natural gas from The Bear. But Putin may be slowed by the bear market rising to meet him, according to a poll of investors by Bloomberg. The United States should start selling natural gas to the region. More…