Ahmed Elgoni felt like he’d struck gold. The 24-year-old video game developer from South Africa had in November secured a ticket to the Game Developers Conference in San Francisco — a cultural mecca for anyone who wants to make video games.
A sponsor would cover the cost of his round-trip flight from Cape Town. Just two weeks ago, he received his visa to enter the U.S.
Then President Trump signed an executive order banning refugees and travelers from seven countries.
Elgoni grew up in South Africa, but he was born in Sudan — one of the countries...