A heated debate has recently erupted between two groups of supporters of President Donald Trump. The dispute concerns the H-1B visa system, the programme that allows US employers to hire skilled foreign workers in specialty occupations – mostly in the tech industry. On the one hand, there are people like Donald Trump’s former strategist Steve Bannon, who has called the H-1B program a “total and complete scam”. On the other, there are tech tycoons like Elon Musk who think skilled foreign workers are crucial to the US tech sector. The H-1B visa programme is subject to an annual limit of...