In a 2015 file photo, a U.S. Customs and Border Protection agent looks from above at a stretch of the Rio Grande that forms the border between Texas and Mexico. President Donald Trump said this week that he will be sending National Guard troops to help with security along the southern U.S. border. (The Minnesota Star Tribune)

Time elapsed from an Easter Sunday Fox News story about a "caravan" of asylum-seekers to a presidential directive sending National Guard troops to the U.S.-Mexico border: six days.

Before one can even weigh the merits of President Donald Trump's latest move, it must first be said that this is no way to conduct national policy, particularly not policy that upends the lives of possibly thousands of men and women who will assist the U.S. Border Patrol, but also serve as visual props, judging from the fact that the president says he wants troops there until his border wall is built.

It's not that using troops to help secure the border is unprecedented. It is not. Every president since Ronald Reagan has done so. In fact, between Presidents George W. Bush and Barack Obama, the U.S. had troops on its southern border for eight of 12 years, ending in 2016. But the rationale for those deployments was clearer, and the rhetoric surrounding them less aggressive.

Under Bush, 29,000 troops ultimately served in Operation Jump Start, assisting in surveillance, drug interdiction and construction of border fencing and road barricades. That was part of an orderly response to annual illegal crossings that had hit the million-person mark at a time when the border patrol was about half its current size. And Bush took pains to work with Mexico and refer to that nation as a friend and ally.

The Obama effort, longer but lower-key, intercepted more than 100,000 crossings and 300,000 pounds of drugs, all while Mexican and U.S. officials continued various other joint efforts on bilateral issues.

Those operations were considered effective, if costly. The price tag for Jump Start alone came in at $1.2 billion.

What is markedly different about Trump's initiative is that it appears to be emanating not from some well-documented need or careful policy consideration, but from a presidential rant triggered by embarrassment over the lack of wall funding and an annual pilgrimage of asylum-seekers and activists, leaving his staff to hurriedly slap together a policy shift that remains skimpy on details. Illegal immigration from Mexico hit a 46-year low in 2017, and while numbers are up for March, they are fairly typical of seasonal migration patterns.

Trump has been needlessly belligerent, whipping up anti-immigrant sentiment and accusing Mexico of "laughing at our dumb immigration laws." His bellicosity has turned a standard presidential tool into a weapon that is further damaging U.S.-Mexico relations. The Mexican Senate has already called on President Enrique Peña Nieto to suspend joint efforts on organized crime and other concerns until Trump exhibits the "civility and respect that the people of Mexico deserve."

The chaotic nature of the Trump presidency is rooted in this reactive approach that turns molehills into mountains, needlessly adding drama and danger through overblown rhetoric. This year's "caravan," with its large numbers of women and children, hardly represents the apocalyptic threat to national security painted by both Trump and his newly appointed Homeland secretary. People are fleeing the turmoil that threatens daily life in Honduras, Guatemala and other countries south of Mexico. They are protected by a humanitarian act passed by Congress in 2008 and signed into law by Bush that sought to protect victims of trafficking.

Some have made the case that while well-intentioned, that law has served as a magnet for unaccompanied minors. But if Trump seeks to stop its use, he must go through Congress to do so. The same holds true for his wall. Failure to get congressional funding does not entitle him to raid the military budget or to use National Guard troops for what may be a mostly symbolic gesture.