Dmitry Medvedev, deputy chairman of Russia’s Security Council and a close ally of President Vladimir Putin, has escalated tensions with the United States by invoking Russia’s “Dead Hand” nuclear system in response to President Donald Trump’s recent warnings. Medvedev’s chilling threat, posted on social media on July 30, came after Trump’s July 28 ultimatum at Turnberry, Scotland, giving Russia 10-12 days to agree to a Ukraine ceasefire or face crippling tariffs on its oil buyers. Medvedev’s Nuclear Warning Medvedev, a former Russian president, warned that continued U.S. pressure, including Trump’s tariff threats and approval of new weapons for Ukraine, could trigger Russia’s “Perimeter” system, known as “Dead Hand.” This Cold War-era automated mechanism is designed to launch nuclear strikes in...