According to a leaked Department of Homeland Security report, completing Donald Trump's wall along the US-Mexico border will cost $21.6 billion. Give or take. That's about twice that of Trump's own estimate.

Because money is kind of hard to imagine at the scale of governmental budgets, I did some quick math that might put things into perspective. For $21.6 billion dollars, you could hire about 65,000 border patrol agents at $40,000 per year for 10 years. Add in the 20,000 agents already patrolling the border and staffing checkpoints, and we have 85,000 agents in all to span a roughly 2,000 mile border. Subtract the 700 or so miles that are currently already fenced, and the open range needing to be patrolled is down to 1,300 miles, not accounting for natural barriers.