Michael Rubin for the American Enterprise Institute: Is it a foregone conclusion that a U.S.-Mexico border wall would be a multi-billion-dollar folly?

The answer to this is no. Walls do have a history of doing their job and, indeed, they are the tried-and-true go-to strategy almost everywhere that security or illegal migration is a concern … So, let’s consider the precedent of walls and systems designed to maintain security and keep illegal immigrants and terrorists out while allowing legal immigrants and visitors in: