The depressing new data on foreign populations in countries around the world

One in 10 people living in OECD countries were foreign nationals in 2018. Many are no longer there. The Covid-19 pandemic has been a magnetic force that is pushing immigrant workers out of their adopted homes and pulling them back to their homelands.

The US’s non-citizen population declined from March to July, dipping to the lowest level of the past two decades in June before rising in July. Excluding short-term visitors, foreign nationals made up about 6.8% of the US population at the beginning of the year. It stood at...