“Build a Wall Around the Welfare State”

For a long time, I’ve been meaning to post a pithy comment on immigration policy from the Cato Institutes’s Bill Niskanen.
The comment was related to the proposal to erect a wall between the United States and Mexico, in order to reduce illegal immigration. Some libertarians favor open immigration. Others believe that so long as we have a large welfare state, open immigration would impose high costs on the taxpayer, and thereby reduce economic growth. (I believe that I read Milton Friedman supporting this latter position, in the year or two before he died in 2006.)
In this context, Niskanen’s pithy comment has appeal:

“Build a wall around the welfare state, not around the country.”

Source:
William A. Niskanen on 11/19/07 at the meetings of the Southern Economic Association in New Orleans.