Welcome to the age of presidential sabotage. Since assuming office, President Donald J Trump has shown little inclination to “take care that the laws be faithfully executed”, as commanded by the US constitution. Instead, he has openly declared his intention to wreak havoc in key programs.

He has appointed officials known to be sworn enemies of their own agencies. He has gutted protections for students, consumers, women, workers, and the environment. And he has threatened to inflict staggering damage on US insurance markets – unless opponents bend to his will and repeal the Affordable Care Act.

But nowhere has Trump proved more effective at undermining federal programs than his own executive orders. There, wielding his Twitter handle like a doomsday device, Trump has displayed an unparalleled flair for self-sabotage. This will hold true, however, only if courts recognize that Trump’s statements must be taken seriously.

“Exhibit A,” of course, is the widely reviled travel ban, which has been blocked by federal courts largely on the basis of Trump’s own animus-laden statements. After repeatedly expressing the prejudice that birthed this policy, Trump has struggled, and failed, to escape his own words.

On Tuesday, Trump’s prior remarks struck again. Citing the president’s televised threat to punish California, a federal judge blocked Trump’s order to strip “sanctuary cities” of federal funds unless they capitulate to his demand that they cooperate with federal immigration officials. (Sanctuary cities are jurisdictions that limit their cooperation with the federal government when it comes to deportation.) This ruling was a crippling blow to Trump’s campaign against cities that decline to assist certain immigration enforcement programs.

Trump's order to restrict 'sanctuary cities' funding blocked by federal judge Read more

While the “sanctuary city” movement is longstanding, it has become exceptionally important under Trump, who has all but declared war on undocumented migrants. In many cases, policies of non-cooperation reflect local views about how to reduce crime and increase public trust in the police. They also reflect core principles. As San Francisco’s mayor said in response to Trump’s order: “We will not give in to threats, or political grandstanding. Together, the Bay Area will stay true to our values of inclusiveness, compassion and equality, and united against any and all efforts to divide our residents, our cities, and our country.”

In challenging Trump’s order, two sanctuary cities, San Francisco and Santa Clara, argued that it was riddled with constitutional flaws: the order is impermissibly vague; it denies due process before stripping federal funds from cities; it unlawfully commandeers localities and forces them to carry out federal immigration law; and it violates the separation of powers by seizing from Congress the power to impose conditions on federal funds. This last argument is especially compelling: Trump’s order plainly exceeds limits on his power to tell cities that they must comply with whatever new policies he makes up, on pain of losing billions of dollars.

Faced with this battery of allegations, Trump’s lawyers retreated. Tacitly conceding that the order is indefensible if taken seriously, they mounted a bizarre, technical defense: in their telling, the plaintiffs lacked standing because the order didn’t do anything, changed no conditions on federal funds, and may not ever be enforced against anyone.

As Judge William Orrick pointed out, though, the executive order required agencies to “ensure that jurisdictions that fail to comply with applicable federal law do not receive federal funds, except as mandated by law.” And that sure looks like a change in policy: “It instructs the [agencies] to do something that only Congress has the authority to do – place new conditions on federal funds.” What’s more, many other features of the order unmistakably contemplate a broader effect than simply enforcing the status quo.

Judge Orrick therefore scoffed at the invitation to treat Trump’s order as “an ominous, misleading, and ultimately toothless threat.” And he bluntly dismissed the idea that “the order is an example of the president’s use of the bully pulpit.” An executive order, he emphasized, “carries the force of law.” The president’s formal act that purports “to create real legal obligations” cannot be read as a “mere policy statement . . . that is fully self-cancelling and carries no legal weight.”

Trump’s alternative argument – that the plaintiffs had not proven a credible threat of enforcement – fared even worse. Here, Trump’s own words came back to haunt him in Judge Orrick’s ruling: “On 5 February 2017, after signing the executive order, President Trump confirmed that he was willing and able to use ‘defunding’ as a ‘weapon’ so that sanctuary cities would change their policies.”

After quoting similar remarks by Sean Spicer and Attorney General Jeff Sessions, Judge Orrick returned to Trump: “President Trump specifically threatened to defund California, stating: ‘I’m very much opposed to sanctuary cities. They breed crime. There’s a lot of problems. If we have to we’ll defund, we give tremendous amounts of money to California … California in many ways is out of control.”

As Niko Bowie observed last week, these public comments immediately shattered Trump’s legal defense: “[He] might as well wave the white flag to San Francisco, Santa Clara, and all the other places challenging the order in court.” It’s tough to argue that nobody is really threatened by an order when your client – the president – is literally on TV threatening people.

This wasn’t the first time, and it surely won’t be the last, that courts are asked to take Trump at his word. In many cases, Trump’s word may spell doom for his policies, given his comfort with tweeting forbidden motives and threatening opponents. In important constitutional and administrative cases, courts will have to reckon like never before with well-supported attacks on presidential motive and intent. Presumptions of deference, good faith, and regularity will certainly come under unyielding strain. While Barack Obama’s public statements were sometimes used against him in court, the sheer frequency and relevance of Trump’s public comments on so many issues will dramatically raise the stakes.

Trump’s defenders will thus have no choice but to argue that we just can’t take Trump at his word. They’ll insist that his campaign statements are uniquely off limits; that his motives are endlessly mysterious; that he’s just engaging in public and political advocacy; that formal doctrines forbid any judicial inquiries into motive; and that his statements are unrelated to policies and decisions issued by other parts of the executive branch. And they’ll impugn judges who take Trump seriously, as White House chief of staff Reince Priebus did in describing Judge Orrick’s ruling as “bananas”.

As the nation reels under the onslaught of one tweetstorm after another, punctuated by incendiary interviews, it’s easy to grow desensitized – and to conclude that Trump’s words mean nothing, either to him or to anyone else. Professor Laurence Tribe accurately captured the lurking danger here: “[A] constant, unyielding, numbing fire hose of complete and utter bullshit – some of it barely intelligible – that engulfs Trump and everyone around him in a suffocating, disorienting haze that blurs the boundaries of truth and all but eviscerates the very notion.”

That impulse is understandable, but must be resisted at all cost. While Trump seems dead set on sacrificing his credibility, so that he may speak without legal consequence, the fact remains that he is president of the United States. His words are deeds, and that is nowhere more true than alongside executive orders.

Everything he says and does can shape our national destiny. He holds lives in his hands. No matter how overwhelming the flood of improper statements, Trump is the president. Every word matters. Every word must be taken seriously. Especially in this era of presidential sabotage, the rule of law means little if the president’s word means nothing.