Agree. What do we spend for Afghanistan per year? $10 billion? $20 billion? $5 billion for the wall now will pay for itself in reduced future spending on illegals.
Afghanistan is an expense. The wall is an investment.
The Pentagon reported last year that we spend $45 billion per year on Afghanistan.
https://www.pbs.org/newshour/politics/pentagon-says-afghan-war-costs-taxpayers-45-billion-per-year
... and the Iraq and Syria military budget is close to $20 billion a year, so that along with Afghanistan’s $45 billion makes it roughly $5 billion per month spent in these war zones.