Russian President Vladimir Putin has warned Western countries that there is a genuine risk of nuclear war if they sent their own troops to fight in Ukraine, and he said Moscow had the weapons to strike targets in the West. Addressing parliament and other members of the country's elite, the 71-year-old repeated his accusation that the West is bent on weakening Russia, and he suggested Western leaders did not understand how dangerous their meddling could be in what he cast as Russia's own internal affairs. He prefaced his warning with a specific reference to an idea, floated by French President...