Critics say hardball tactics could come back to haunt Moscow. Alexander Medvedev went to Davos with the tall task of convincing European leaders and others that they have nothing to fear from the state-controlled Russian energy giant Gazprom. The company enraged European leaders earlier this month when it temporarily shut off the flow of oil through a key pipeline due to a dispute with Belarus. The move came a year after it had similarly clamped off natural gas supplies due to a dispute with Ukraine. "I'd like to assure all of the people in this room there is no reason...