Donald Trump sat down with Fox News’ Laura Ingraham this week and, not surprisingly, the president was eager to focus on immigration. He bragged about having “called up the military” to block Central American migrants from seeking asylum in the United States.

It led to an interesting exchange:

INGRAHAM: What is the military going to be able to do? Obama and Bush both sent the National Guard and it had no effect. TRUMP: But they’re not me. They’re not me. I’m sending up the military. This is the military. And they’re standing there and one thing that will happen when they are captured, we don’t let them out. What has been happening, and we are not, as of pretty recently, we are not letting them out.

The first part of the president’s answer was completely bizarre. We already know, for example, that many of the troops currently at the U.S./Mexico border are, in fact, members of the National Guard. That was true when other recent presidents made deployments, and it’s true now.

But even putting that aside, Trump seemed to draw a distinction between the National Guard and the military. Told that his predecessors dispatched the Guard to the border, this president said, “I’m sending up the military. This is the military.”

Right, but the National Guard is part of the military, too. Given his on-air remarks, it wasn’t clear that Republican understood this rather basic detail.

As for Trump’s boasts about what the military will do under the current policy – I use the term “policy” loosely – the Washington Post’s fact-check described the president’s rhetoric as “misleading.”

The Posse Comitatus Act of 1878 restricts what the U.S. Armed Forces can do to enforce domestic policies, including immigration laws. “The armed forces do not appear to have a direct legislative mandate to protect or patrol the border or to engage in immigration enforcement,” according to an April 2018 report by the nonpartisan Congressional Research Service. However, the Armed Forces can provide indirect support, the CRS report added. They can “share information collected during the normal course of military operations; loan equipment and facilities; provide expert advice and training; and maintain and operate equipment,” for example. […] What the Armed Forces cannot do is detain or frisk migrants, according to a federal law that bars “direct participation by a member of the Army, Navy, Air Force, or Marine Corps in a search, seizure, arrest, or other similar activity unless participation in such activity by such member is otherwise authorized by law.”

It’s difficult to say whether Trump believes his own rhetoric, but either way, his chest-thumping about what troops will do at the border should not be taken at face value.