Ignore Trump if you want. But don't deny the lessons of other parts of the world facing an immigration crisis

From following the news, you'd think that immigration was strictly a U.S. problem, one brought to the fore by Donald Trump. But although Trump has certainly moved the debate to a new level here at home, other parts of the world are facing an immigration crisis that is, if anything, worse. And there are lessons in that.

The European Union, for example, is now beset with a flood of "migrants," mostly from Africa and the Middle East. Some of them are fleeing war and civil strife; others are heading for a place with more economic opportunity — or, at least, with welfare benefits that dwarf what they could earn at home through hard work.

Most of Europe operates under what's called the Schengen Agreement, which abolished border controls among 26 European nations. Once within the Schengen Area, "any person, irrespective of nationality, may cross the internal borders without being subjected to border checks."

This worked tolerably well for a while, but now, with hundreds of thousands (maybe millions) of migrants in Europe or on the way, some European nations are beginning to have second thoughts. These have redoubled in the wake of last weeks attempted terrorist attack on a Paris to Amsterdam train, staged by a supposed Moroccan migrant. Although the European Union has so far ruled out any change to the Schengen agreement, officials from France, Germany and Belgium are talking about changes. The problem is that, right now, once migrants get into the EU, they can easily travel to where benefits are the highest, overwhelming locals. Germany, the most popular destination, is straining to accommodate all the arrivals. It's reached the point that a German mayor, Boris Palmer, is talking about seizing private homes to accommodate migrants, a measure that is about as popular among citizens as you might expect.

One nation that isn't part of the Schengen Agreement is Britain; to get from the rest of Europe into Britain you still have to show a passport and (depending on your home country) a visa. This policy, combined with Britain's better economy, has led to refugees piling up across the Channel in France. Refugee camps (The New Republic refers to a migrant "jungle") have bloomed in Calais, where the Channel Tunnel connects to Britain, and migrants have rioted, broken into trucks, and stowed away on trains in an effort to get to the English promised land.

This has led the British foreign secretary, Philip Hammond, to suggest that they need to be sent home. With the gap in living standards between Europe and Africa, Hammond said, the motivation to migrate would otherwise be insuperable. (Historiesof the 19th-century colonial era talk about "Europe's scramble for Africa." That has led wags, such as Ross Douthat, to talk about today in terms of "Africa's scramble for Europe." In both cases, the motivation is money.)

Meanwhile, as Americans talk of a border fence, Bulgaria is building one, with razor wire and steel 12 feet high. And Slovakia is flat-out refusing to accept Muslim migrants, viewing them as dangerous and destabilizing. Migrants have massed at the Macedonian border and are creating tensions between Serbia and Hungary. Hungary is building a fence too. Norwegian politicians are suggesting that Norway should do something similar to Australia, which is sending unwelcome refugees to New Guinea or to prison.

As the numbers of migrants climb, and countries become weary of accommodating them, expect these tensions to grow.

So it's good news and bad news. The good news is that immigration concerns aren't just a problem for the United States. The bad news is that they're a problem for the entire First World. What to do about it? Nobody seems sure. But although open borders are a nice idea, the fact is that countries differ in economics, in culture and in politics. No country can accept and assimilate an unlimited number of outsiders, and when the number exceeds a threshold, a backlash is certain. Thresholds are being exceeded, and backlashes are building, all over the world.

So it's not just Trump. America, like the rest of the world, will have to decide what it wants to do about the fact that more people want to live here than we can accept. It is simple political reality that the problem can't be ignored forever.

Previously:
• 08/21/15 Fast moving bad news builds prosperity
• 08/14/15 Trump indicts America's ruling class
• 08/07/15 Politicos put past before progress
• 07/15/15 When party outsiders feel ignored, a champion appears to take their interests to heart --- or at least sounds as if he does
• 07/08/15 Are happier lawyers, cheaper legal fees on the horizon?

Comment by clicking here.

Glenn Harlan Reynolds, a University of Tennessee law professor, is the author of The New School: How the Information Age Will Save American Education from Itself and is a columnist at USA TODAY.