Nic Robertson is CNN's international diplomatic editor. The opinions in this article belong to the author.

(CNN) It is possible, even probable, that Donald Trump will leave office smarter than when he went in -- even if he still insists he is often the smartest one in the room.

He'll have learnt that Twitter is not the best forum for high-stakes diplomacy.

Trump will also have learned why hanging up on major allies like Australia's Prime Minister Malcolm Turbull is not a good idea, or that embarrassing guests, as he did twice with German Chancellor Angela Merkel, is counterproductive.

First, during her visit in April he ignored her request for a handshake in the Oval Office. Then at their joint press conference he joked, "As far as wiretapping, I guess, by this past administration, at least we have something in common perhaps," in reference to the Obama administration's tapping of German phones.

Merkel was left looking uncertain as others in the large room collapsed in laughter. It was awkward and cringeworthy and no way to host friends.

It's not clear if the lesson has been learned yet, but it is symptomatic of the uncertainty and lashings of chaos Trump has brought to international diplomacy.

His top-tier appointees -- Vice President Mike Pence, Secretary of Defense James Mattis and Secretary of State Rex Tillerson -- have spent a good part of their first 100 days traveling the world picking up after the President's missteps.

Collectively, they might be finally catching up to where previous administrations had been on day one , but their commander in chief still has a long way to go.

His first 100 days have taught him some of the basics that most modern Presidents already appreciated before coming to office.

On NATO for example, he came to office saying that it was "obsolete" and not doing enough on fighting terrorism.

A few days into office, he greeted British Prime Minister Theresa May at the White House. She seemed to surprise him at the press conference following their meeting, telling Trump "Mr. President, I think you said, you confirmed that you're 100 percent behind NATO."

He didn't deny it, and sent Pence and Mattis to Europe to tell European leaders the same. However it would be another two-and-a-half months before he would bring himself to say it publicly.

That finally came when hosting NATO chief Jens Stoltenberg at the White House in April: "I said it (NATO) was obsolete, it's no longer obsolete". That's what his allies really wanted to hear.

Even so, Trump couldn't bring himself to say he was wrong. He went on to claim credit for refocusing the alliance on terrorism, something it has been doing for over a decade, most notably by deploying troops to Afghanistan in 2002 to support the US take down of al Qaeda.

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On China, Trump has been on another a steep learning curve. In the early days in office he branded President Xi Jinping a "currency manipulator." Yet by the time he was hosting the Chinese President at Mar-a-Largo in Florida, he'd come to realize this enemy could be a friend.

And with US national security facing an even more implacable enemy, North Korea's Kim Jong-un, Xi has gone from foe to favorite. "I have great respect for the President of China," Trump said last week, apparently pleased that China is putting pressure on the hermit kingdom to end its nuclear weapons ambitions.

It's fluidity in thinking that Trump believes is a virtue: "I'm proud of my flexibility," he said a few weeks ago. Yet to many watchers he seems not so much flexible as impressionable.

He seems to take his lead from the last leader to whom he has spoken. Whether it's Merkel on trade with Europe or Xi on the history of the Korean peninsular, it somewhat highlights his grasp of global detail that given a few facts, he thinks he's fixed the knowledge deficit.

In the overall arc of his first 100 days, North Korea has been one of the principle accelerants to the President's flexibility , teaching him that an enemy will pick the worst time to act up.

Kim decided to test missiles while Trump was having lunch with Japanese Prime Minister Shinzo Abe at his club, Mar-a-Largo.

A side lesson he may have taken on board was not to do national security on a public patio between the salad and main course. Trump was pilloried when photos emerged showing him and his national security team dealing with their first major security issue -- at dinner, in public. Many of these lessons are only pulling Trump towards what many would have considered entry level for the job.

On Syria, however, he seems to have caught up to the Obama administration's position. By bombing Assad for using chemical weapons, he may have now surpassed it. But, as with Korea, he still lacks a coherent strategy on the war-ravaged nation that takes him diplomatically beyond Obama's position.

There was another significant lesson for Trump in the aftermath of his dropping bombs in Syria: friends can become enemies overnight.

Until recently he touted Putin as a possible ally, early this year saying that "if Putin likes me, I consider that an asset, not a liability."

But Putin, Assad's biggest sponsor, has fast become a foe.

Where he promised so much coming in to office -- "My number one priority will be to dismantle the deal with Iran" -- Trump has little to show for it.

And on another sound bite that this time last year sounded easy to deliver -- "Bomb the s**t out of them (ISIS)" -- Trump has been learning the limits to his power.

While he enabled MOAB, the mother of all bombs, to be dropped on ISIS in Afghanistan, it amounts to a pinprick in the over all battle and not a sea change in tactics.

In his book "The Art of the Deal", Trump defines his business style as a tough negotiator creating uncertainty. As President he has yet to finesse the tactic so only his enemies don't know his next move.