Within the first few months of Donald Trump becoming president, the number of apprehensions at the border with Mexico plunged.

Trump celebrated the decline specifically as validation of his policies and his approach to migration. (Later in the year, The Post’s Nick Miroff speculated that the drop was probably linked to concern over Trump’s rhetoric about immigration.)

“You see what’s happened,” Trump said at a town hall event in April 2017, a month when apprehensions hit a new low. “Sixty-one percent down now in terms of illegal people coming in. Way, way down in terms of drugs pouring into our country and poisoning our youth. Way down. General Kelly” — John F. Kelly, who was Trump’s homeland security secretary at the time — “has done a great job.”

A few weeks later, those low April numbers were reported.

“It just came out that they’re 73 percent down,” Trump said, referring to the drop since he’d taken office. “That’s a tremendous achievement. Look at this, in 100 days, that’s down to the lowest in 17 years, and it’s going lower. Now, people aren’t coming because they know they’re not going to get through, and there isn’t crime.”

The number of apprehensions was proof that his hard line was working.

But those April numbers were as low as they got. Then this happened.

Obviously evidence that Trump’s policies weren’t working, right? That people no longer felt they weren’t going to get through?

Well, here was Trump on Tuesday morning.

Not only is the number of apprehensions seen as proof of the great job the Border Patrol is doing, but that “GREAT job” is identified as particularly good in relation to how low the numbers were last year.

That’s just breathtakingly dishonest. Not only is Trump flipping his position on the importance of apprehension numbers, but he’s also explicitly disparaging his prior position as necessarily bad. He’s saying, in this tweet, that he was doing a bad job when apprehensions were as low as they were when he bragged about them.

It’s also worth noting that the recent spike is driven by an increase in the number of families arriving at the border. Trump frames the apprehension rate as reflecting a savvy Border Patrol that’s ensnaring illegal border crossers. In reality, the surge in families being apprehended is in part a function of those families immediately turning themselves in upon arrival at the border to seek asylum.

In other words, not only is the increase in apprehensions at odds with Trump’s rhetoric two years ago, it’s also an attempt to overhype the new increase in apprehensions.

It’s important to note, too, that the increase in apprehensions is significant over the short term but that, over the long term, the number is not exceptionally high.

By Trump’s 2017 standard, Barack Obama did a better job on the border because he had fewer apprehensions than Trump does now.

By Trump’s current standard, George W. Bush did a better job on the border because he had more apprehensions than Trump does now.

But, really, by Trump’s standard in any given moment, no one is doing better on the border than Donald J. Trump.