Donald Trump began his presidency as a reluctant traveller but he seems to be getting a taste for it. After his squabbles with the G7 in Canada and his bromance with Kim Jong-un in Singapore, the US president will in a few weeks' time once more venture forth onto the world stage.
This time Air Force One will descend on Brussels for the four-yearly summit of the North Atlantic Treaty Organisation. And in many European capitals, ministers are already biting their nails.
They know they will once again be urged by Mr Trump to spend more on their own defence. But what is worrying them more is the fear that Nato will be the next multilateral international organisation to be subject to the president's diplomatic fire and fury.
Last weekend the G7 summit was dominated by Mr Trump's decision to impose trade tariffs on his allies, a divisive act that meant the meeting ended in acrimony. The president signed up to the final communiqué and then withdrew his support, criticising his Canadian host with insulting tweets from Air Force One.
And now he has taken the extraordinary step of using this transatlantic trade dispute to cast doubt on his support for Europe's collective defence. "We protect Europe (which is good) at great financial loss, and then get unfairly clobbered on Trade," he tweeted. "Change is coming!"
So what might that change be? Well, from the G7 in Canada and the North Korea/US summit in Singapore, we have a clearer perspective of the diplomacy of Donald J Trump.
Mr Trump appears to treat most diplomatic problems as he does a business deal. He picks a fight, he escalates it, and then he tries to do a deal. By turns he threatens and he charms, pushing the brinkmanship as far as he can.
Thus the sudden announcement that the Singapore summit was to be cancelled and then the equally fast decision to reinstate it. Much of his diplomacy involves personal attacks, such as mocking the North Korean president as "rocket man". He told Fox News this was deliberate: "I think without the rhetoric we wouldn't have been here."
Mr Trump's diplomacy also includes the unexpected moments. He likes to surprise his interlocutors as much as his own staff and allies. The initial offer of a summit to the North Koreans came from nowhere. The decision to suspend joint military exercises with the South Koreans came as news to the South Koreans.
This diplomacy is all about him: it is instinctive, intuitive, driven by how he feels on the day. Mr Trump said he would know "in the first minute" if President Kim was up for a deal.
His is also the diplomacy of the showman: the photo opportunities, the handshakes, the walks in the park. In Singapore, Mr Trump even got his staff to make a celebratory film previewing the summit in the portentous tones of a movie trailer.
This is a diplomat who writes his own scripts, raising expectations with seemingly absurd hyperbole and then marking his own homework. After the Singapore summit, Mr Trump tweeted, "there is no longer a Nuclear Threat from North Korea", which came as news to the Japanese and South Koreans.
Ah, yes, those tweets: short but not always sweet. Twitter is the vehicle through which Mr Trump largely communicates, a medium he controls without having to bother with State Department diplomats shaping the language.
The substance of Mr Trump's diplomacy is as distinctive as the style. At its heart seems to be a rejection of multilateralism. He appears to believe that the US is no longer able to project its power through multilateral institutions like the G7 or the United Nations.
He arrived late for the G7 and left early, hardly bothering to hide his impatience. Instead Mr Trump prefers the simplicity of the one-on-one deal, the bilateral discussion between like-minded leaders, the balancing of national interest and power.
Mr Trump's diplomacy is not as unique as some might think. He is not the only leader in the world today whose instinct is more national than international.
Nor is he the first president to rely on personal chemistry to seal a deal. Think Reagan and Gorbachev in the 1980s. Think Nixon and Mao in the 1970s.
Mr Trump is also not the first leader to adopt a foreign policy that plays deliberately to his domestic political base, fulfilling his campaign promises to abandon the Iran nuclear deal and impose tariffs on Chinese steel.
So Mr Trump's diplomacy is not unique, but nor is it without risk. At times he seems to act without planning the next steps. In part, this reflects his impulsive character. It also reflects a State Department that is severely understaffed.
This was most apparent when the president withdrew the US from the Iran nuclear deal. The European powers asked the White House what the next move would be from the US. And answer came there none. There was no Plan B to try to seek a new deal with Iran. The fury in Europe was very real.
The problem with deals based on Mr Trump's gut instinct is that they may not always be right.
There are risks in a diplomacy that is deeply personal. Relations between nations are not just expressed by how well the leaders get on. They are based also on state-to-state engagement, the institutional links and shared values and experience that live on long beyond any individual terms of office.
His focus on America's narrow economic and security interests has echoes of the traditional isolationism that dominated US thinking through parts of the 19th and 20th centuries.
The German foreign minister, Heiko Maas, said in a speech this week: "The Atlantic has become wider under President Trump. His policy of isolationism has left a giant vacuum around the world."
Some see in Mr Trump's diplomacy a blurring of distinctions between allies and enemies, a sense that the world is instead full of countries that one chooses to deal with or not. The contrast between Mr Trump's praise for a North Korean dictator with an appalling human rights record and his insults for a traditional ally such as Canada could not be clearer.
When asked on Fox News about all the bad things Mr Kim had done, Mr Trump was dismissive: "Yeah, but so have a lot of other people done some really bad things."
So this is the diplomacy of President Trump. It is a diplomacy that has got the US and North Korea talking rather than threatening one another with nuclear war; a diplomacy that asks questions of a global internationalism that many believe failed the people of Syria; a diplomacy that surprises, and makes the geopolitical weather.
But it is also a diplomacy that seems to divide as much as it unites, a diplomacy that challenges a rules-based international order that many believe constrained the destructive nationalism of the 20th century and brought peace to billions of people.
Next stop, the Nato summit in July.