President Trump, in another episode of his extended temper-tantrum over the wall he is getting, now threatens to “close the border.” Unfortunately, the media repeats it, as though it’s a coherent dare. It’s meaningless, and the media should point it out.

What would “closing the border” entail? By definition, illegal immigrants intend to cross the border without authorization, so “closing” means . . . I’m not sure. If he wants more money so the Department of Homeland Security can do a better job securing the border, he should take the Democrats' offer of $1.3 to $1.6 billion in new money. Unfortunately, the government shutdown means that nonessential DHS personnel are furloughed, and I’m not sure what rejecting more money and keeping DHS employees at home accomplishes. It doesn’t “close the border.”

Maybe the president means he won’t let legal residents and citizens back into the country from Mexico. That’s not legally possible. Trump cannot keep out people who, well, have a legal right to be here. Moreover, such a move would destroy a good deal of the economy of border states (e.g., Texas), and wreak hardship on the rest of us. Someone should ask border-state senators and governors — who generally do not even support the wall — how an attempt to shut the border would affect their states.

Perhaps he means he is going to deny all asylum claims. However, two federal courts have already held that his efforts to curtail or redefine asylum are legally and constitutionally ineffective.

As we and others have pointed out, Judge Emmet G. Sullivan, in his 107-page opinion, explained that “it is the will of the Congress — not the whims of the Executive” that determine the process for denying asylum claims. He permanently enjoined the administration from removing migrants in the United States “without first providing credible fear determinations consistent with immigration laws.”

Listen, even Fox News analyst Andrew Napolitano fesses up: “[The president] cannot legally do it. We know that because of federal statutes. They were last revised in 1986 when our relationship with migrants coming north was very different than it is now.” He continued that migrants who have an asylum claim, “meaning you are escaping a government that is pursing you, or escaping a government that is failing to enforce basic law and order, can enter the U.S. The president doesn’t want to hear this but it’s the law.”

So why does Trump say such nonsense? It’s unclear whether he thinks he has the power to do this, or if it logistically possible. He probably doesn’t care or know what is possible at this point; he’s busy whipping his base into a fury. But here’s the thing: If he has the power to “close the border,” why does he need a wall?

The media does the country a disservice by simply repeating Trump’s threat without pointing out that it is meaningless. It should insist that the president explain what he means.

Good news! Beginning Jan. 3, a Democratic-controlled House can call administration officials to testify and ask them directly, “What the heck is Trump talking about?” It should make for gripping TV.