walls

For those that think building a wall is a keen idea, there’s this:

“The way we teach students is we say, in general, the unintended consequences of immigration reforms are more important than the intended consequences,” said Philip Martin, a farm immigration expert at UC Davis….

Many experts believe that the current pattern of illegal immigration from Mexico and Central America was a consequence of the 1986 law’s border tightening – followed by a tougher crackdown in 1996 that built fences in San Diego and El Paso.

“The perverse effect has been to dramatically lower return migration out of the country,” said Douglas S. Massey, a Princeton University sociologist and co-director of the Mexican Migration Project, a longitudinal survey of more than 18,000 migrants, the largest of its kind. “So we’ve transformed what was before 1986 a circular flow of workers into an increasingly settled population of families. We have actually accelerated the rate of undocumented population growth in the United States and shifted it from a relatively less costly population of male workers into a much more costly population of families.”

The problem, he said, is that by making border crossing “very risky and unpleasant and increasingly expensive, you prolong the length of the trips, you reduce the probability of return migration, and you make it more likely that migrants … just hunker down and stay.”

The rate of migration from Mexico has actually stayed constant for the last two decades, Massey found. But the rate of return has fallen by half, from 50 percent to 25 percent….

Via Reason.