When doing things he shouldn’t, Donald Trump is a hyperactive president. He blurts high secrets to Russian visitors. He fired the FBI director who investigated things Mr. Trump wished to hush up. Mr. Trump spreads disinformation, tweets abuse and hurls paper towels at Puerto Ricans like a dog owner dispensing treats. From the actual work of the American presidency, however, Mr. Trump’s disengagement is extreme.

Mr. Trump is not merely shirking work, although he is. He is wrecking the systems that enable presidents to work effectively. The United States government agglomerates giant bureaucracies, each with its distinct mission and culture, often riven by generations of mistrust. (Ancient joke: Briefing the Chief of Naval Operations, a junior officer refers to the Soviets as “the enemy.” The CNO halts him. “The Soviets are our adversary. The Air Force is the enemy.”)

To yoke these agencies to a common purpose, a complex group of coordinating agencies has been stacked atop them inside the Executive Office of the President. These agencies have been at best neglected — at worst sabotaged — by the Trump presidency.

Let’s start with America’s most lethal domestic challenge: the fight against drug addiction. A terrible epidemic of overdoses killed some 63,600 people in 2016, up from an already horrifying 52,000 in 2015. The casualties for 2017 will prove higher still, according to preliminary government reports.

A dozen federal agencies share the job of responding to this crisis, supporting the governments of 50 states plus the District of Columbia and Puerto Rico. Some agencies interdict drugs from abroad. Some regulate drugs manufactured at home. Some prosecute drug dealers. Some rehabilitate drug addicts. Some educate at-risk populations. Bringing order to this vast undertaking is the mission of the Office of National Drug Control Policy (ONDCP) within the White House.

Although Mr. Trump campaigned hard on the opioid crisis, he did not get around even to nominating a director of the ONDCP until September. He then picked about as bad a choice as could be imagined: Tom Marino, a member of Congress who had led the fight to make it harder to police imports of suspicious pharmaceuticals, receiving hundreds of thousands of dollars of campaign contributions and lobbying expenditures from the industry along the way.

What qualified Mr. Trump’s choice for the job? He was the fifth member of Congress to endorse Mr. Trump during the 2016 campaign — and the first from the must-win state of Pennsylvania.

The nomination quickly unravelled under withering criticism. Today, nearly a year into the Trump administration, the director’s job at ONDCP remains vacant.

Versions of that story can be told for almost every function of government in the Donald Trump years.

The most important domestic-side function in the White House is the Office of Management and Budget. Mr. Trump appointed a hyperideological director, Mick Mulvaney. As a leading figure in the House Republican “freedom caucus,” back in 2011 Mr. Mulvaney declared his willingness to force a default on U.S. government obligations in order to win a budget battle. That’s already strange preparation for a budget chief.

But even stranger is that Mr. Mulvaney has declined to regard his staggeringly demanding role as a full-time job. Alongside the OMB directorship, Mr. Mulvaney has also accepted an appointment as acting director of a powerful regulatory agency, the Consumer Financial Protection Bureau. (His task there is to roll back protections extended during the presidency of Barack Obama.)

Maybe because Mr. Mulvaney is so distracted, the budget process — always a mess — has degenerated into near chaos in the Trump years. His administration still has not passed a budget for the fiscal year that commenced three months ago. Instead, the government has been funded by stopgap “continuing resolutions,” premised on trillion-dollar deficits indefinitely — deficits, in times of comparative peace and prosperity, bigger than those the George W. Bush administration ran during the Iraq war or that the Obama administration ran during the worst economic crisis since the 1930s.

Mr. Trump campaigned on “getting tough” on trade. He commenced his administration by withdrawing from negotiations for a new Trans-Pacific trade treaty. He has threatened to withdraw from the North American and U.S.-South Korean trade treaties, too, unless he gets better terms.

Trade is shared across almost as many agencies as the drug-abuse portfolio. Treasury has a voice, for example, as does State. The coordinating agency here is the U.S. Trade Representative. This job Mr. Trump did fill (although there is still no head of either USTR’s technology or agriculture office). Having named a reasonably plausible — although protectionist-inclined — trade lawyer as the trade representative, Mr. Trump then handicapped him by creating a second coordinating body, a “National Trade Council,” and appointing as its head a protectionist polemicist with meagre professional qualifications: Peter Navarro. Mr. Navarro so alarmed the U.S. business community that in September, his office was joined to that of White House economic adviser Gary Cohn — effectively putting three people in charge of the trade portfolio, a practice even more destructive to policy-making than failing to name one.

The results have been deeply threatening to world prosperity. Mr. Trump is hacking away at existing trade arrangements without even beginning to put anything in their place. Worse, the United States has been completely absent from the most important trade negotiation anywhere on Earth: the talks between Britain and the European Union on post-Brexit treaties.

The Trump administration is contemplating war in the Korean peninsula: a 30-per-cent likelihood, according to South Carolina senator and born-again Trump ally Lindsay Graham. At the same time, it has repeatedly threatened a trade war against South Korea, the most important military partner against North Korea.

The most globally consequential of the Trump wrecking projects has been his sabotage of the National Security Council. The NSC has grown into a substantial bureaucracy in its own right. At its core is a “principals committee”: a regular meeting of the most important people in the U.S. government. Amazingly, Mr. Trump’s first appointments to the principals’ committee excluded the Chairman of the Joint Chiefs of Staff and the Director of National Intelligence. Mr. Trump instead included his son-in-law, Jared Kushner, and Steve Bannon, the white-nationalist blogger who had served as one of Mr. Trump’s campaign chairmen. (Among the other chairs and managers were Paul Manafort, now in legal jeopardy for failing to disclose his work as a paid agent of the Russian government; and Corey Lewandowski, who lost his job after he was arrested for battery of a female reporter.)

Over the course of the year, Mr. Trump’s NSC has become less bizarro. Mr. Bannon was removed from the principals committee, then from the White House – and has now spectacularly split with the President altogether. Trump’s first national-security adviser, Michael Flynn, was forced to step down after 24 days, and has now pleaded guilty to lying to the FBI. Mr. Trump’s first deputy national-security adviser — former Fox News talking head K.T. McFarland — who had last worked in government as a speechwriter and communications aide back in the 1980s — was demoted. More appropriate people have replaced them. The intelligence and military chiefs were added back onto the principals committee. Many of the weirdos and security risks who previously prowled the NSC corridors were removed, or at least lost security clearances.

Yet even now, the system does not work. Every week, the United States’ allies must make sense of some jarring new outburst. What security can South Korean and Japanese allies feel when Mr. Trump boasts of the size and strength of his “nuclear button” — indifferent to the fact that those two countries are already within range of a North Korean attack?

Is the Iran deal still in place or not? Will the United States negotiate with North Korea without preconditions? On even these basic questions, there is no clear Trump administration policy (although the President has now clarified — or at least claimed — that his “nuclear button” is larger and more powerful than that of Kim Jong-un). The National Security Strategy released in December described Russia as a revisionist competitor to the United States; Mr. Trump, in his speech releasing the strategy, praised Russia as a partner.

Nobody is able to impose order. Crucial jobs remain empty even now. There is no ambassador to Germany: The President’s nominee, Richard Grenell, a famously vituperative blogger and television personality, is stalled in the Senate, likely because the Germans have communicated that he would be unwelcome in Berlin. For nearly a year, there was no ambassador to Spain, a country that could have used the help of its friends to soothe the national-unity crisis in Catalonia. Past ambassadors to the European Union have included such luminaries as Stuart Eizenstat (formerly President Carter’s top domestic-policy adviser) and C. Boyden Gray (an eminent lawyer and close friend of George H.W. Bush). The post is currently vacant, because Mr. Trump’s first choice was exposed as a serial fraudster, and the President hasn’t gotten around to selecting another.

Where the Trump presidency inherited a policy from its predecessors, it has sometimes been able to continue that policy to successful outcomes. Combat operations against Islamic State-held cities in Iraq started under Mr. Obama and have nearly reached their completion under Mr. Trump.

But when it comes time to do something new, the administration is baffled. The capture of Islamic State territory has not put an end to the IS threat. The Islamic State will dematerialize into a terrorist network, recruiting online and striking inside other countries — as an IS-inspired Bangladeshi immigrant struck Times Square in New York last month. What then? Who’s planning postconflict operations in Iraq and reconstruction in Syria? Who knows? If it cannot be done by the U.S. Department of Defence operating alone and uncoordinated with other agencies or other countries, it probably will not be done at all.

Mr. Trump subverts executive-branch institutions in order to aggrandize his own power. Maybe the most ominous of his attacks on these coordinating mechanisms is his drive to convert the Department of Justice and FBI into his own personal police force.

Historically, the president oversees law enforcement, but he does not control it. He sets priorities: more or less attention to this or that area of federal jurisdiction. He does not direct the FBI to target or exempt this or that individual. If the president thinks a person has been treated unfairly, he has the pardon power — but of course, a pardon is a public act. What the president is never supposed to do is whisper quietly to the FBI, “This person is a friend of mine, please go easy on him; this person is an enemy, please arrest him.”

To protect the integrity of the law, the United States has evolved an elaborate system of rules and restrictions governing the relationship between the president, prosecutors and police. All communications between White House staff and the FBI are supposed to be routed through the White House counsel’s office, and the White House counsel is usually a lawyer of high reputation.

Mr. Trump, by contrast, chose as his White House counsel a combative partisan — who happened to be the nephew of the top lawyer for Mr. Trump’s Atlantic City casino operations back in the 1980s. Mr. Trump’s short-tenure communication director Anthony Scaramucci actually tried to order FBI investigations on his own authority. And Mr. Trump himself fired FBI director James Comey when Mr. Comey refused an order to shut down the investigation of Russian interference in the 2016 elections.

The last time a president fired an FBI director, back in 1993, it happened as a result of credible allegations of abuse of expense accounts — and after lengthy consultations with Congress. The claim that a president can fire a director who refuses to obey an order to stop an investigation is a shocking departure from a century of federal practice. Yet, suddenly, that very claim is being asserted by this White House, by Trump allies in Congress, and by pro-Trump talkers on TV. The whole system of fencing law enforcement from politics is under attack, and not by Mr. Trump alone.

And as law enforcement has resisted Mr. Trump’s politicization, the President has turned against the law enforcers. He has vilified the FBI in his speeches; his partisans have defamed special counsel Robert Mueller and his staff; and his own Department of Justice has leaked the personal communications of FBI agents who texted negative comments about Mr. Trump. (One of those agents called Mr. Trump “a loathsome human being … an idiot”: a harsh opinion, but one apparently shared by the President’s own Secretary of State, Rex Tillerson, who reportedly called Mr. Trump a “moron” after a Pentagon meeting on July 20, and by Mr. Trump’s national-security adviser, H.R. McMaster, who reportedly called him a “dope” and an “idiot” at a private dinner with Oracle senior executives two days earlier. A new book by Michael Wolff quotes other Trump aides — and Fox News owner Rupert Murdoch — all describing the President in similarly contemptuous language.)

Richard Nixon famously warned, half a century ago, that the United States might dwindle into a “pitiful, helpless giant.” Under Mr. Trump, the U.S. government has been decapitated into a staggering, headless giant. By design and by mistake — to cover for his wrongdoing and because of his own vast carelessness and indifference — Mr. Trump is sabotaging the institutions and agencies that protect the United States and sustain the peace of the world. The insider reports from Washington accurately portray a man unworthy of the presidency.

However petty the man, his legacy for bad is huge and growing — not only for Americans, but for America’s friends and partners worldwide.