Foreigners fuel American prosperity

It’s easy to despise Elon Musk as a supremely loathsome powermad egomaniac. But he’s also the richest man in the world, and he got that way by immigrating to the United States and seizing the opportunities he found here to foster advanced technologies, from electric vehicles to rockets.

Musk knows something about building companies, creating jobs and boosting economic growth. And one key to that su…