A friend of ours who grew up in South Texas has some strong feelings about Donald J. Trump’s “big, beautiful wall.”

We had dinner with him and another friend this evening and we chatted about this and that — shared a few laughs along with a few groans.

Then our conversation turned to Trump’s wall. Our friend was blunt.

It won’t work.

It won’t keep out the criminals.

It is a foolish gesture meant only to appease those who voted for the president of the United States.

Our friend is a highly educated man. He has family still living in South Texas, not far from the Rio Grande River. Build a wall? Who’ll pay for it? The president says Mexico will foot the bill. How is that going to happen on a structure meant to be built on the American side of its lengthy border with Mexico.

This good buddy of ours has considerable knowledge of life along our border. I’ll accept what he knows and what he has seen.

He acknowledges that the bad guys — the drug dealers and human traffickers — already have carved out extensive tunnel networks all along our southern border that would enable such activity to continue.

Moreover, my pal has asked, how is the president going to stop illegal immigrants from entering from either end of the U.S-Mexico border — from splashing ashore from the Pacific Ocean or the Gulf of Mexico?

Just think, Trump believes he can underwrite construction of the wall by levying a 20-percent tariff on all goods imported from Mexico. Who pays the tariff? You and I do — when importers pass the increased cost of the imports to their American customers.

Yep, that’ll show them Mexicans.