We were promised a world without borders. In 1990 the Japanese management consultant and business school professor Kenichi Ohmae published “The Borderless World,’’ in praise of global supply chains. In 1996 John Perry Barlow penned his Declaration of the Independence of Cyberspace, addressed to the “governments of the industrial world.” He told them defiantly: “Cyberspace does not lie within your borders.”

Just over two decades later, borders are back. In his speech last week to the United Nations General Assembly, President Trump was unequivocal: “We must uphold respect for law [and] respect for borders.”

Like Trump’s reference to the North Korean dictator, Kim Jong Un, as “Rocket Man” and his threat to “totally destroy” Kim’s country, this was calculated to appall the people Steve Bannon calls “globalists.” Yet Trump’s assertion of national sovereignty was one of the few lines in the speech that won applause. 

The world itself is not in a globalist mood. Brexit is about reasserting sovereignty, above all over immigration. Angela Merkel was reelected as German chancellor on Sunday, but her party’s share of the vote was reduced, mainly because she lost control of Germany’s borders two years ago. And Trump himself clings to his election promise to build a wall along the US-Mexican border, as well as to exclude from the United States the citizens of mainly Muslim countries associated with terrorism.

European elites sneer compulsively at Trump, but polls show that majorities of their citizens would support a similar ban on Muslim immigration into the European Union. Meanwhile, the same European elites are ramping up their efforts to tax and regulate the principal beneficiaries of the borderless world, the giant American tech companies of Silicon Valley.  ...