The more things go kaflooey for Donald Trump at home, the trickier and less malleable he becomes for the rest of the world. This equation was surely apparent to anyone in his path in Brussels and Taormina last week – including the Prime Minister of Montenegro, who was physically repositioned by Trump at his most oafish as he barged to the front for a “family photo” at Nato.

Had anyone been hoping for a less testy Trump they were surely disappointed. At Nato, he might have recognised the sacrifices of nations much smaller than his fighting the Taliban in Afghanistan instead of delivering a scolding to virtually every other member nation allegedly for stiffing the American taxpayer in their contributions to the Alliance. He might also have refrained from calling the Germans “very bad” for being very good at selling their cars in America.

“Euro Trashed”, blared the front page of the Daily News in New York the following day: “Don shoves a Prime Minister, Insults Germany”.

But for Trump to be in a better mood, we need be nicer to him. Melania could start by not snatching her hand away from his. There were moments during his trip when it seemed as if the other leaders had stage-managed events to make him look foolish on tape. I am suspicious of Emmanuel Macron, the President of France; the way he walked straight for Trump at Nato and swerved at the last minute to greet Angela Merkel instead: not subtle.

With his shoulder pads and cockatiel hair, Trump does not look short on confidence. He is the leader of the most powerful nation on Earth. But we all see signs of a man chronically uncertain of how the rest of us perceive him. A confident Trump wouldn’t obsess over every cruel joke about him on Saturday Night Live. A confident Trump wouldn’t feel compelled to snipe petulantly at his every foe on Twitter. A confident Trump wouldn’t Sellotape his tie to his shirt.

He wouldn’t want our pity – that would negate the very essence of his political brand, “Trump the Strong”. But he shouldn’t worry: if Americans are generally protective of their presidents in rough times, I hazard that may not apply to him. Those who did not vote for him – that’s most of them – only get more disdainful. His supporters won’t pity him either because they are too busy spitting at those they think are out to hurt him: reporters, especially, and now German car makers too. Now even they may be having second thoughts.

Melania made the headlines last week after swatting her husband's hand away when he reached for hers (AFP/Getty Images)

Nate Silver of the the fivethirtyeight website gives us a clue as to why the President’s state of mind might be more fragile than ever. He queries the conventional wisdom that, whatever hits the fan in Washington, his core level of support remains unaffected.

“To the contrary, Trump’s base seems to be eroding,” Mr Silver reveals. “There’s been a considerable decline in the number of Americans who strongly approve of Trump, from a peak of around 30 per cent in February to just 21 or 22 per cent of the electorate now.”

He adds: “Far from having unconditional love from his base, Trump has already lost almost a third of his strong support.”

The loss stands to reason when you consider the progress Trump’s been making on things he promised voters. Everywhere he tries to go, he ends up hitting a wall – and not the one he wanted us to talk about, either. The most recent exhibit: federal judges again blocking his attempts to impose even a watered-down version of his ban on Muslims and Syrian refugees entering the country. The Supreme Court may have to deal with it, but that would be months away.

Macron grimaces as Donald Trump attacks Nato during 9/11 memorial speech

The pledge to repeal Obamacare is hardly in any less trouble after the Congressional Budget Office declared last week that even the new and improved version of its replacement, passed by the House, would mean 23 million more Americans losing their health insurance over ten years and premiums rising sharply for the elderly and the sick. Now the Senate must pass its own version of the bill: but don’t hold your breath. The Republicans have the slimmest majority in the upper chamber and are are deeply divided on the issue.

In the meantime, the White House has just sent a budget blueprint to the Hill that includes draconian cuts to all manner of programmes, including foreign aid, that stand no chance of getting congressional approval. By most accounts, it is a document that was dead on arrival.

To get things done in Washington, presidents need to have political strength, even when their party controls both chambers of Congress. Trump has less and less of that vital commodity. And part of the reason, of course, is the swiftly expanding investigation into Russia’s meddling in the 2016 election and what collusion there may have been between Moscow and his campaign. Add to that concern that Trump himself may have crossed a legal line asking heads of investigative agencies, including James Comey, the now sacked FBI director, to slow-march their probes.

In pictures: President Donald Trump on tour Show all 39 1 /39 In pictures: President Donald Trump on tour In pictures: President Donald Trump on tour 20 May 2017 US President Donald Trump and Saudi Arabia's King Salman bin Abdulaziz al-Saud arriving for a reception ahead of a banquet at Murabba Palace in Riyadh Getty Images In pictures: President Donald Trump on tour 20 May 2017 US President Donald Trump, accompanied by First Lady Melania Trump, and Saudi Arabia's King Salman bin Abdulaziz al-Saud being welcomed at Murabba Palace in Riyadh Getty Images In pictures: President Donald Trump on tour 20 May 2017 US President Donald J. Trump with King of Saudi Arabia Salman bin Abdulaziz Al Saud during a welcome ceremony with traditional sword dancers at Murabba Palace, in Riyadh, Saudi Arabia EPA In pictures: President Donald Trump on tour 20 May 2017 King of Saudi Arabia Salman bin Abdulaziz Al Saud with US President Donald J. Trump and wife Melania during a welcome ceremony at Murabba Palace, in Riyadh, Saudi Arabia EPA In pictures: President Donald Trump on tour 20 May 2017 US President Donald Trump adjusts the Collar of Abdulaziz Al Saud Medal, after it was bestowed upon him by Saudi Arabia's King Salman bin Abdulaziz Al Saud at the Royal Court in Riyadh, Saudi Arabia Reuters In pictures: President Donald Trump on tour 20 May 2017 Saudi Arabia's King Salman bin Abdulaziz Al Saud presents U.S. President Donald Trump with the Collar of Abdulaziz Al Saud Medal at the Royal Court in Riyadh, Saudi Arabia Reuters In pictures: President Donald Trump on tour 21 May 2017 Palestinians print posters depicting US President Donald Trump in preparations for his planned visit, in the West Bank town of Bethlehem Reuters In pictures: President Donald Trump on tour 21 May 2017 US President Donald Trump accompanied by first lady Melania Trump, his daughter Ivanka Trump and her husband White House senior advisor Jared Kushner, before delivering his remarks to the Arab Islamic American Summit in Riyadh, Saudi Arabia Reuters In pictures: President Donald Trump on tour 21 May 2017 US President Donald Trump looks on as U.S. Secretary of State Rex Tillerson and Saudi Arabia's Crown Prince Muhammad bin Nayef exchange a memorandum of understanding Reuters In pictures: President Donald Trump on tour 21 May 2017 First Lady Melania Trump shares a laugh with a child during a visit to the American International School in the Saudi capital Riyadh Getty Images In pictures: President Donald Trump on tour 21 May 2017 US President Donald Trump holds a bilateral meeting with Bahrain's King Hamad bin Isa Al Khalifa AP In pictures: President Donald Trump on tour 22 May 2017 Israeli soldiers rest during preparations ahead of President Trump's landing in Tel Aviv, Israel Getty Images In pictures: President Donald Trump on tour 22 May 2017 First Lady Melania Trump makes her way to board Air Force One in Riyadh as she heads with her husband the US President to Israel Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and first lady Melania Trump board Air Force One for Israel, the next stop in Trump's international tour, at King Khalid International Airport AP In pictures: President Donald Trump on tour 22 May 2017 Israeli soldiers wait for the arrival ceremony of US President Donald Trump at Ben Gurion airport near Tel Aviv, Israel AP In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and first lady Melania Trump arrive aboard Air Force One at Ben Gurion International Airport in Lod near Tel Aviv, Israel Reuters In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and first lady Melania Trump disembark Air Force One on arrival at Ben Gurion International Airport AP In pictures: President Donald Trump on tour 22 May 2017 US President Donald J. Trump and his wife, US First Lady Melania Trump are welcomed by Israeli Prime Minister Benjamin Netanyahu upon arrival at Ben Gurion Airport, in Lod outside Tel Aviv, Israel EPA In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump and Israeli Prime Minister Benjamin Netanyahu sit during welcome ceremony in Tel Aviv AP In pictures: President Donald Trump on tour 22 May 2017 US First Lady Melania Trump chats wife Sara Netanyahu as US President Donald Trump chats to Israel's Prime Minister Benjamin Netanyahu during a welcoming ceremony to welcome Trump at Ben Gurion International Airport Reuters In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump delivers a speech upon his arrival at Ben Gurion International Airport in Tel Aviv Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump gestures during a press conference with Israel's President at the President's Residence in Jerusalem Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump watches as First Lady Melania Trump signs the guest book at the President's Residence in Jerusalem Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump walks with first lady Melania Trump in Jerusalem's Old City Reuters In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump visits the Western Wall, the holiest site where Jews can pray, in Jerusalems Old City Getty Images In pictures: President Donald Trump on tour 22 May 2017 US President Donald Trump stands next to Rabbi Shmuel Rabinowitz at the plaza in front of the Western Wall, Judaism's holiest prayer site, in Jerusalem's Old City Reuters In pictures: President Donald Trump on tour 22 May 2017 US Secretary of State Rex Tillerson and White House senior advisor Jared Kushner leave notes at the Western Wall in Jerusalem Reuters In pictures: President Donald Trump on tour 22 May 2017 US First Lady Melania Trump touches the Western Wall, Judaism's holiest prayer site, in Jerusalem's Old City EPA In pictures: President Donald Trump on tour 22 May 2017 Ivanka Trump, assistant and daughter of US President Donald J. Trump, touches the Western Wall, Judaism's holiest prayer site, in Jerusalem's Old City EPA In pictures: President Donald Trump on tour 22 May 2017 President Donald Trump visits the Western Wall AP In pictures: President Donald Trump on tour 24 May 2017 US President Donald J. Trump arrives in a vehicle to Saint Damaso's Court for a private audience with Pope Francis in Vatican City EPA In pictures: President Donald Trump on tour 24 May 2017 Pope Francis walks past Ivanka Trump and First Lady Melania Trump on the occasion of the private audience with President Donald Trump, at the Vatican AP In pictures: President Donald Trump on tour 24 May 2017 Pope Francis exchanges gifts with US President Donald Trump during a private audience at the Vatican Getty Images In pictures: President Donald Trump on tour 24 May 2017 Pope Francis meets US President Donald Trump and his wife Melania during a private audience at the Vatican Reuters In pictures: President Donald Trump on tour 24 May 2017 Pope Francis with US President Donald J. Trump EPA In pictures: President Donald Trump on tour 24 May 2017 Pope Francis gets into is car after meeting with US President Donald Trump AP In pictures: President Donald Trump on tour 24 May 2017 President Donald Trump and his wife Melania look at the frescoed ceilings during their visit to the Sistine Chapel at the Vatican L'Osservatore Romano/Pool Photo via AP In pictures: President Donald Trump on tour 24 May 2017 US President Donald Trump security vehicles are seen in front of Air Force One before take off from Leonardo da Vinci-Fiumicino Airport in Rome, Italy Reuters In pictures: President Donald Trump on tour 24 May 2017 US President Donald Trump and First Lady Melania Trump wave to reporters before boarding the Air Force One to Brussels, at the end of a 2-day visit to Italy including a meeting with Pope Francis at the Vatican, at Rome's Fiumicino international airport AP

We have no idea what either special counsel Robert Mueller or the various investigating committees on the Hill will find when all is said and done. But even if it is nothing of any real legal significance, it will have damaged Trump and his administration by compounding the paralysis of his agenda. Paralysis, not impeachment, may end up being his final downfall.

This is the Trump who came to Belgium and Italy. Were things going better at home, he might not have felt compelled to stand outside Nato and speak not really to the leaders around him or the world at large but rather to his base at home. The verbal beating he gave the allies was for their benefit, never mind statesmanship. If he is still refusing to commit to the Paris Treaty on climate change it is because he has to be more worried about his base than about the planet.