Russia and Iran's Marriage of Convenience

Iranian President Hassan Rouhani reunited with Russian President Vladimir Putin in Moscow for a high-profile visit Tuesday that was clearly meant to telegraph to the world -- and the United States in particular -- that the strategic alliance between Iran and Russia is stronger than ever. After all, as Putin put it, the relationship stretches back 500 years. But neither Putin nor Rouhani has forgotten the intense bouts of geopolitical competition between the two powers over those five centuries. That underlying distrust could be felt this week even as the leaders worked to deepen their ties....