I wrote in Politico today pushing back against the argument that a border wall is immoral:

If a wall is immoral, what standing does the current 350 miles of primary fencing have? Isn’t it just as hateful as what Trump proposes? The $5 billion the president wants wouldn’t even match what we already have—it would construct about 150 miles of new barriers where none currently exist.
With funds already appropriated, the Department of Homeland Security has replaced more than 30 miles of border barriers and contracted out for more barriers in the Rio Grande Valley, Arizona and California. It has done this without American becoming noticeably a more closed society.
A wall or fencing is relatively mild as far as immigration enforcement goes. It doesn’t involve deporting anyone. It doesn’t separate families. It doesn’t prosecute and detain anyone. It doesn’t deny any illegal immigrant currently working in the United States a job. All it does is seek to avoid getting in a situation where any of these things is necessary in the first place.
A wall doesn’t close down the border, or close us off to the world. There are still ports of entry. People can still travel to and from Mexico. People can still, for that matter, fly to Paris. It just diminishes illegal entry at certain strategic points.