Today just as Pope Francis leaves Washington, DC, Chinese President XI Jinping arrives for meetings with President Obama. One of the main purposes of his trip is to demonstrate how important having China as a trading partner is to the U.S. economy.The U.S. has always been a top destination for foreign visitors, whether they are private tourists or heads of states. Residents of Washington, DC are accustomed to seeing presidents and prime ministers paying the obligatory visit to the White House. They may complain about the street closings and traffic snarls as foreign dignitaries move about the city under tight security, but most accept such problems as simply being part of living and/or working in the nation's capital.Even the most blasé of...