The historic U.S.-Cuba talks are under way and they may have attracted a new addition to the Havana port. The Russian spy ship Viktor Leonov CCB-175 parked there Tuesday, laden with high-tech software, radar and 30-millimeter cannon and anti-aircraft guns, replacing a cruise ship that had been there the day before. Normally, the surveillance ship travels up and down the American Eastern Seaboard in international waters, with its radars pointed in the direction of the United States. On Tuesday, however, just as the Americans were due to arrive for big talks with Cuban officials—the first such high-level talks held in...