The US is making the immigration of skilled workers more expensive; the UK is exploring ways to make it cheaper. It is tempting to conclude that one of them must be wrong. But which?

President Donald Trump’s eye-catching proclamation that $100,000 will be added to the cost of new H-1B visas (which are granted temporarily to skilled workers) raises two separate questions. The first is, because most voters seem to have a strong desire to limit immigration, are fees a good way to do that?

There are other systems. A government could limit the number of visas, and allocate them by lottery. This is the current US system, and a modified lottery will continue to apply if there is still enough demand at the new price. Or it could use some kind of “points-based” allocation, trying to figure out what kind of people it would like to admit — people with family already in the country, people of the right age, people with the right qualifications, people with the right experience.