President Trump speaks in the Rose Garden at the White House Friday to declare a national emergency so he can build a wall along the southern border. (Evan Vucci)

The lawyers will fight over the legality and constitutionality of President Trump’s national emergency declaration. What his legal team can’t salvage is the American people’s assessment of his ability to do his job. Trump’s rambling and disjointed explanation for his decision is a perfect example why so many independents and former Republicans find him unacceptable.

The performance really has to be watched to be believed. China, North Korea, Britain and trade policy found their way into the talk. One word seemed to spark a thought and off he would go chasing it, like a dog catching the scent of a truffle and wandering off into a forest in search of it. Other famous moments of presidential free association, like President Reagan’s much derided concluding statements in the first 1984 debate, are Shakespearean in comparison.

Like it or not, words matter when you are president. They are a president’s strongest weapon. With them, he or she can move nations and shift debates. Words can inspire trust between hostile leaders, such as the trust between Reagan and his Soviet adversary Mikhail Gorbachev. With words, a president can move mountains and change the world.

If words fail, a president is left with two weapons to achieve his goals: will and force. The Constitution constrains the president’s ability to achieve much with either of these tools, as the men who wrote it were well aware that these twin brothers are forever the weapons of potential tyrants even if patriots can use them to great effect in times of crisis. For every Lincoln, history shows us a hundred would-be Caesars who use will and force to exalt themselves at the expense of their people.

Trump’s critics have long warned that the president was Caesarean at his core, and they will surely raise that point again in opposing his declaration. But that concern now seems overwrought. Even the modern tyrants whom the president too often unctuously praises demonstrate more facility with language and more attention to governing detail than does he. To borrow from popular culture, Trump looks less like the sinister Emperor Palpatine and more like the hapless Jar Jar Binks.

The moderate independents and former Republicans who have opposed the president look at these displays with disgust. They are disproportionately college-educated, and if there is one thing our universities instill, it is facility with and respect for the use of words. A leader who can’t string together an original coherent paragraph loses these voters’ respect. They couldn’t imagine working for or living with someone so ruled by his instincts rather than his mind, and they can’t imagine entrusting such a person with the most important office in the world.

Yet there is no political future for Trump or his agenda unless at least some of these people change their minds. Their defection gave the Democrats the House. Their votes will determine who becomes president in two years. Even if the Democrats nominate someone whose views trouble them greatly, they won’t hold their nose and vote for Trump a second time if they can’t respect him in the first place.

Everyone has their bad days, and Friday morning’s speech was significantly worse than normal even for a man whose rhetorical style will never be confused with Cicero’s. Reagan used a scripted line about Democratic opponent Walter Mondale’s “youth and inexperience” to earn some laughs and overcome the fallout from his earlier slip. But Reagan was the most eloquent Republican president in well over half a century. He had a deep well of respect to draw upon, as even many of his adversaries marveled at his use of words.

Trump’s friends, advisers and family need to come to grips with this glaring and persistent weakness. Trump must start talking to the college-educated people who resist him and at least try to do so in a manner and language they can understand. If he does not, then his administration will look more and more like an isolated sand castle waiting to be washed away by the tide of public opinion.