President Trump. (Nicholas Kamm/AFP via Getty Images)

President Trump’s directive initiating action on a wall along the southern border has upset relations with Mexico and left in its wake the resignation of the Border Patrol chief.

Mexicans, along with many other reasonable people, were offended by Trump from the first day of his presidential campaign because of his slurs about Mexican immigrants as rapists, criminals and drug runners. President Enrique Peña Nieto demonstrated his anger with Trump’s executive order by canceling a trip to Washington for a high-level meeting.

It doesn’t take X-ray glasses to see Border Patrol Chief Mark Morgan’s resignation as a Trump gift to the National Border Patrol Council (NBPC), which supported the president’s candidacy. After Trump’s victory in November, the union executive board wrote an article for the alt-right Brietbart.com, formerly run by top Trump’s chief strategist Stephen K. Bannon. The headline left no doubt about the union’s position: “Border Patrol Agents: The Chief Obama Gave Us Is a Disgrace.”

NBPC is one of two federal employee unions that endorsed Trump during his presidential campaign.

NBPC President Brandon Judd and Chris Crane, president of National ICE Council, the other federal union that backed Trump, attended his immigration speech at the Department of Homeland Security on Wednesday. They received personal presidential shout-outs.

Addressing these “two friends of mine,” Trump said, “You guys are about to be very, very busy doing your job the way you want to do them.”

The Federal Insider spoke with Judd on Thursday about the president’s initiatives. Morgan’s resignation was announced after the interview. When I asked Judd about it later, he said he had no information. But given his close relationship with Trump, Judd is probably somewhere smiling.

Here are edited questions and answers from that conversation.

Apprehensions, a key measure of illegal immigration, have dropped dramatically over the past decade, so why is a wall necessary?

Judd: There’s not as many people crossing, but just because the number of people crossing are fewer, that doesn’t indicate whether or not the border is secure. What indicates whether or not our border is secure is the effectiveness rate. If we’re detecting and arresting nearly everybody that crosses the border illegally or all of the contraband that’s coming across the border illegally, that determines whether or not the border is secure. Unfortunately, we’re not even close. Of illegal persons crossing the border, we arrest about one out of every two. Contraband, we’re a lot less effective.

I do support the wall in strategic locations. We’re not talking about a continuous wall from California to Texas.

The wall is going to be very expensive, perhaps $20 billion. Couldn’t that money be better used elsewhere, for more technology such as  sensors and cameras, for example?