On “The McLaughlin Group,” John McLaughlin asks if the United States should impose tariffs on Mexico equal to the cost of providing social services to Mexican immigrants if Mexico doesn’t stop illegal cross-border traffic. Pat Buchanan responded by emphasizing the need for U.S. border security, Eleanor Clift said it would be too costly for Mexico, and Tony Blankley said it would probably be a violation of WTO. Mort Zuckerman said the reaction to such a law in Mexico would move the country far to the left.

It seems to me that all of these insightful pundits missed the point: McLaughlin was proposing that Mexico build a wall to keep Mexicans inside. Immigration advocates sometimes warn that a fence along the border would be “a new Berlin Wall.” But that’s a little over the top; the Berlin Wall was designed to keep East Germans in, to declare them the property of a repressive regime that couldn’t survive if it allowed people to vote with their feet. Whatever its demerits, an American fence would be intended to protect our borders and regulate who could come in.

But McLaughlin’s proposed Mexican wall would be a new Berlin Wall. Anybody can stumble into a bad idea, but it’s disappointing that not one of McLaughlin’s four guests noticed the import of his proposal.