It's President Donald Trump’s diplomatic debut. And the world is holding its breath.

Trump’s meeting on Friday with British Prime Minister Theresa May — his first sit-down with a foreign leader as president — comes with high stakes for the normally cozy “special relationship” of the two allies. It also represents a major test for an erratic and untested politician on the global stage, a day after he inflamed relations with Mexico’s president on Twitter.


“The unpredictability of it is unnerving. She does not know how it’s going to go,” said Julianne Smith, a former national security aide to Vice President Joe Biden.

Foreign governments, which have been bewildered by Trump and unclear about his intentions, will be monitoring the meeting for clues. Will he go off-script and embarrass May or put his guest on the spot? Or will his White House staff choreograph the event smoothly?

“We’ll be watching this meeting very closely” to judge its execution, said one official from a major U.S. ally whose leader will likely meet with Trump soon.

European officials are carefully watching to see how the leader of a country that recently voted to leave the European Union plays her relationship with a new U.S. administration that has shown sympathy with right-wing populists movements on the continent.

The differences between Washington and London often don’t go much fyrther than pronunciation. But as May’s forceful remarks Thursday to congressional Republicans in Philadelphia made clear, she and Trump may be speaking different languages when it comes to dealing with Russia and the future of the European Union.

“It's a trap to be too aligned with Trump” right now, said a European diplomat. “This guy is a total unknown.”

“At the same time, it's difficult for her to be too independent,” given Britain’s looming departure from the EU, he added.

Privately, the British leader may not relish sitting down with Trump, whose condemnations of Muslims she has called “divisive” and whose coarse talk about women she labeled “unacceptable.”

But both the White House and Downing Street are sending positive signals about the meeting, and diplomatic insiders in both Washington and London said that the two leaders both stand to gain from a smooth and friendly confab. Trump is eager to show that he is a credible world leader. May wants to demonstrate that Britain’s strategically invaluable alliance with the U.S. endures in a changing world order.

May began seeking Trump’s favor even before he was sworn in. Officials from her Conservative Party government have paid regular visits to Trump Tower — including Foreign Secretary Boris Johnson, who came despite having said last year that he was “genuinely worried” Trump might become president and joking that he would avoid Manhattan due to “the real risk of meeting Donald Trump.”

Most striking was a kick to the shins her government delivered to Secretary of State John Kerry in December after he criticized Israeli settlement building in a speech. May’s spokesman called the speech, which infuriated Israeli Prime Minister Benjamin Netanyahu, not “appropriate.”

That startled Kerry aides but pleased Trump officials — especially Trump’s son-in-law and senior adviser, Jared Kushner, an Orthodox Jew and strong Netanyahu supporter.

May’s remarks to congressional Republicans sent more positive signals to Trump, including a passage that drew parallels between Trump’s election and her country’s “Brexit” vote to leave the EU.

Just as the U.S. is “renew[ing] your nation just as we renew ours,” May said, adding: “We have the opportunity to lead, together, again.”

But May is hardly in perfect alignment with Trump.

When President Barack Obama first met with May’s predecessor, David Cameron, in March 2009, Obama noted the “shared set of values and assumptions between us.”

Eight years later, that set is substantially reduced.

While May is critical of the EU, for instance, she does not hope for its demise the way Trump adviser Stephen Bannon does. “It remains in our interests, and those of the wider world, that the EU should succeed," May said.

Although May is overseeing Brexit’s implementation, she opposed her nation’s decision to withdraw from the EU, which Bannon and other nationalist thinkers denounce for smothering state sovereignty and heritage.

“The days of the United States backing the European project are over,” said Nile Gardiner, director of The Heritage Foundation’s Margaret Thatcher Center for Freedom.

May’s address to Republicans also urged caution on the question of rebooting relations with Moscow — something Trump has called one of his top foreign policy goals. “We should not jeopardize the freedoms that President [Ronald] Reagan and Mrs. [Margaret] Thatcher brought to Eastern Europe by accepting President Putin’s claim that it is now in his sphere of influence,” May said.

The British leader also hinted at her discomfort with Trump’s rhetoric about Muslims. While calling for a campaign to defeat Islamic radicalism, she added that “we should always be careful to distinguish between this extreme and hateful ideology, and the peaceful religion of Islam and the hundreds of millions of its adherents” — echoing Obama administration language that many conservatives found too conciliatory.

The White House and No. 10 Downing Street have each signaled that the leaders will talk about a new trade deal between Washington and London, one of many bilateral agreements Britain will need to strike in the aftermath of its departure from the EU’s economic network.

The subject of trade also has political resonance: During a visit to London last April, President Barack Obama warned that Britain would be “in the back of the queue” for a trade deal with Washington if it voted to leave the EU.

Trump clearly doesn’t agree and appears happy to reward British voters for defying Obama, as well as their own political and financial elites.

But any boastful talk of a new economic partnership will be just that for now. By law, Britain can’t even begin direct trade negotiations with another country until it has exited the EU, a process expected to take years.

“The U.K., and the U.K. media, will be looking for evidence that it will indeed be possible to deliver a U.S.-U.K. trade agreement in short order,” said Peter Westamacott, who served as British ambassador to Washington from 2012 to 2016.

“The reality is that complex trade agreements cannot be delivered overnight, unless one side is prepared to settle for an unbalanced deal. In practice, they take years to complete,” he added. “And in this case, there are plenty of really difficult issues in financial services, agriculture and so on, which are likely to prove contentious.”

“Trump will be eager to promise her the moon,” Smith said. “But I think they’re essentially kidding themselves if they think they’re going to have big breaking news on the trade front.”