Eight hundred years ago next month, English noblemen forced King John to sign the Magna Carta. It’s still having amazing effects on the world today. The Magna Carta helped usher in government with a separation of powers. It helped create conditions in which centralized authority could not totally control fiscal, political, religious or intellectual life. It helped usher in the modern Anglo-Saxon state model, with its relative emphasis on the open movement of people, ideas and things.

The Anglo-Saxon model has its plusses and minuses, but it is very attractive to people around the world. Today, as always, immigrants flock to nations with British political heritage. Forty-six million people in the United States are foreign born, almost 1 in 6. That’s by far the highest number of immigrants in any country in the world.

Canada, Australia and New Zealand are also immigrant magnets. The British political class was a set abuzz last week by a government report showing a 50 percent increase in net immigration in 2014 compared with 2013. The government has a goal of limiting immigration to 100,000 a year, but, in 2014, net inbound migration was estimated to be 318,000. Britain has the most diverse immigrant community of any nation on earth.

Some of the those people went to Britain from outside of Europe, but a great many flow from the sclerotic economies in the European Union: Italy, Spain and France. Compared with many other European countries, Britain is a job-creating paragon.