Aside from Donald Trump’s bluster about “fire and fury” and Kim Jong-un’s similarly theatrical replies in the manufactured “crisis” of 2017, serious nuclear threats made during an international crisis have been happily MIA for the better part of the past 40 years. Not so now. Less than four days after invading Ukraine’s sovereign territory, Russian President Vladimir Putin ordered his country’s nuclear forces to be placed on “high combat alert”, citing aggressive statements from NATO member states as the main catalyst for the decision.