LAREDO, Texas — About nine miles or so north of Laredo you see a line of motor vehicles pulling off the northbound lanes of Interstate 35.

Big ones, little ones. Long-haul trucks, economy cars, mini-vans full of kids and assorted family members. They all stop as they leave this city of nearly 300,000 residents for points north.

What gives? The “porous border” at this one stop at least isn’t quite so porous.

What are the authorities looking for? As my dear mom used to say: I’ll give you three guesses, and the first two don’t count.

They’re looking for illegal immigrants. They’re looking for human cargo. They are on the hunt for drugs, weapons, you name it.

Now, this particular stop-and-search station doesn’t mean the border is air tight. I get that there remain many other points of entry for illegal immigrants to sneak into the United States of America.

There has been this sort of screening for some time. It’s just that when you see it, you look at the long and growing line of vehicles backing up, you appreciate the difficult job that our Border Patrol and Immigration and Customs Enforcement officers — as well as our state andlocal police agencies — must perform.

Donald “Smart Person” Trump perhaps has done one thing as he has continued to rail against illegal immigration and keeps yammering about building a wall that he suggests Mexico will pay for; it is that he has elevated our border officers’ alertness.

I am hoping they remain alert.