Two simple economics concepts explain why Pres. Trump's proposed wall makes no sense. The first one is opportunity cost -- the value of the next best alternative when a decision is made. The wall will cost at least $18 billion (Pres. Trumps' budget request for the wall). Consider what else could be purchased with $18 billion that would have a major positive impact: funding CHIP for a year, infrastructure improvements, scholarships for low-income students to attend college, etc. It is likely any of these alternatives would have much more value to society than the proposed wall.

The other economic concept is marginal benefits; the additional benefits from increasing some good or service. What would be the additional benefits to the U.S. of building the wall? Given the existing efforts to stem illegal immigration (immigration agents to patrol vulnerable areas, existing fences, etc.), it is likely that the additional benefits from the wall in the form of reduced illegal immigration would be small. Would the reduction in illegal immigration be worth the cost of the wall? Almost certainly not. Let's spend money in ways that truly benefit society and forget about the wall.

BRUCE DOMAZLICKY, Cape Girardeau