Following the Russian invasion of Ukraine and the on-and-off Russian nuclear threats, scholars have been analyzing Europe’s defense capabilities against Moscow’s huge nuclear warhead fleet. Mixed messages from U.S. President Donald Trump about NATO before the alliance’s summit last month have also prompted analyses of whether and how Europe could defend itself in case the United States doesn’t adhere to Article 5 of the NATO treaty that mandates collective NATO defense against any attack on a NATO member state. …