Americans need to take a deep look at the relation between our own policies and two nagging problems. One is the situation in Haiti; the other is the situation in Mexico.

In both cases, our trade policies contributed to crises we now describe another way. We didn’t cause the earthquake that hit Haiti, but our policies (together with International Monetary Fund policy and corruption on the part of the Haitian government) damaged the economy so that the country was less well able to cope with the earthquake than it might have been.

And in the case of Mexico, while we’ve spent money on walls and argued about immigration policy, we could have been dealing with the causes of conditions that are driving millions of Mexicans across the border.

American trade policy undermined the local agriculture of both these nations in the 1990s by flooding them with imported U.S. staples: subsidized corn in Mexico, rice and other imported and donated food in Haiti. Farmers were impoverished, bankrupted, thrown off their land and left to seek their living either in Port-au-Prince or, in the case of Mexicans, in the U.S.

Ex-President Bill Clinton, who as U.N. special envoy to Haiti spent time there after the earthquake, spoke with contrition in March before the Senate Foreign Relations Committee about the effects on Haiti of the North American Free Trade Agreement he signed as president.

“It may have been good for some of my farmers in Arkansas,” said Clinton, who early in his career had been governor of that state, “but it has not worked. It was a mistake. I had to live every day with the consequences of the loss of capacity to produce a rice crop in Haiti to feed those people because of what I did; nobody else.”

He might have said the same thing about Mexico, where 1.3 million small growers went bankrupt between 1994 and 2004 as American corn imports increased tenfold, muscling Mexican corn out of the increasingly centralized tortilla market.

While American agribiz has profited, U.S. taxpayers’ money has gone for barriers, border guards and more policing to stem the tide of people stealing across the border, and to cope with rising violence as poverty south of the border causes the drug trade to become more deeply entrenched.