An Aging Europe in Decline“I’VE fallen and I can’t get up.”These words, shouted by an elderly woman, were made famous in a medical alert device ad in the 1990s. In 2015, they might be Europe’s catchphrase.As the United States economy slowly recovers, analysts across the political spectrum see little to cheer them from Europe. …One bright spot might seem to be immigration. In 2012, the median age of the national population in the European Union was 41.9 years, while the median age of foreigners living in the union was 34.7. So, are Europeans pleased that there will be new arrivals to work and pay taxes when the locals retire?Not exactly. Anti-immigrant sentiment is surging across the Continent. Nativist movements performed alarmingly well in European Parliament elections last year. Europe is less like a grandmother knitting placidly in the window and more like an angry grandfather, shaking his rake and yelling at outsiders to get off his lawn.Arthur C. Brooks, a contributing opinion writer, is the president of the American Enterprise Institute.A version of this op-ed appears in print on January 7, 2015, on page A23 of the New York edition with the headline: Europe’s Decline.