Kathmandu, Feb. 4 -- The brouhaha between the tech bros led by Elon Musk and Donald Trump's nativist supporters over whether to restrict skilled immigrants reflects a deep underlying tension between the politics and economics of migration.

Today's rich economies owe much of their success to migrants who, by choice or through coercion, laboured on their plantations, factories, mines, and homes. Even now, these countries continue to rely on low- and high-skilled migrant workers to fuel economic growth and dynamism by taking on jobs that native-born workers are unwilling or unable to fill.

Far from displacing local workers, migration tends to boost employment among native-born citizens. Studies have consistently shown that countries with ...