A vast majority of migrants move from a poor to a less poor country, not a rich one. Immigration quotas should be based on how much the host country has ruined other countries. Britain should have quotas for Indians and Nigerians; France for Malians and Tunisians; Belgium for very large numbers of Congolese.

And when they come, they should be allowed to bring their families and stay — unlike the “guest workers” who were enticed to build up the postwar labor force of the colonizers and then asked to leave when their masters were done exploiting them.

The Dominican Republic, where the United States propped up the dictator Rafael Trujillo for three decades, should be high on the American preference list. So should Iraq, upon which we imposed a war that resulted in 600,000 deaths. Justice now demands that we let in 600,000 Iraqis: for each death we caused there, someone should get a chance at a new life here.

Some 12 million Africans were enslaved and carried across the Atlantic by European powers. Should not 12 million people from Africa be allowed to live in the countries enriched by the toil of their ancestors? Both will be better off: the African still suffering from what slavery has done to his country, and the host country that will again benefit from African labor, but this time without enormous pain and for a fair wage.

Just as there is a carbon tax on polluting industries, there should be a “migration tax” on the nations who got rich while emitting greenhouse gases. The United States is responsible for one-third of the excess carbon in the atmosphere; Europe, another one-quarter. A hundred million refugees fleeing hurricanes and droughts will have to be resettled by the end of the century. The United States should take a third, and Europe another quarter.