LONDON — Prime Minister Boris Johnson of Britain, known for his bombast and outspokenness, begins his first foreign trip as leader on Wednesday walking a daunting diplomatic tightrope, ostensibly trying to pry Brexit concessions from stony-faced Europeans while keeping a wary eye on his domestic opponents with a general election possible in the fall.
And looming over it all for the new prime minister is the vexing problem of President Trump.
Mr. Johnson will speak about Brexit with the German chancellor, Angela Merkel, in Berlin, on Wednesday, and the French president, Emmanuel Macron, in Paris on Thursday. But the talks are not expected to break the deadlock that has poisoned and paralyzed British politics for three years.
Then it will be on to Biarritz, France, for a weekend meeting of the Group of 7 countries, where he will have to carefully calibrate his relationship with President Trump, an enthusiastic backer of Brexit who is deeply unpopular throughout the Continent and among Britons.
Mr. Johnson, who has stepped up preparations for the possibility of a potentially chaotic no-deal Brexit on Oct. 31, needs the president’s help if he is to strike a trade deal with the United States to cushion the economic impact. But he can ill afford to appear too chummy with him.
“Johnson’s friendship with Trump and their joint admiration society is a liability for him with the Europeans,” said Julianne Smith, a former United States deputy national security adviser now with the Center for a New American Security, who recently finished a fellowship in Berlin.
“The closer he allies himself with Trump the more difficulty he’ll have going forward with the Europeans, from trade to security,” she said.
Nor would a closer relationship be popular with large numbers of British voters who heartily dislike Mr. Trump, not least for his positions on Iran and climate change. Mr. Trump early on abandoned the Paris climate accord, and last year, he pulled out of the 2015 Iran nuclear deal, which Britain, France and Germany still support. Mr. Trump is expected to try to draw Mr. Johnson away.
There is growing speculation that Mr. Johnson is aiming for a general election, said Charles Grant, director of the Center for European Reform, a research institute based in London, since his working parliamentary majority has dwindled to just one. But that presents other perils.
“If he is going into an election, he has to be very careful not to be seen as Trump’s poodle,” he said. The opposition Labour Party leader, Jeremy Corbyn, is already trying to disparage Mr. Johnson as “Britain’s Trump.”
With an eye to that, Mr. Johnson might try to shift the blame for the Brexit impasse onto his European neighbors by painting them as obdurate, Mr. Grant said. The prime minister has also sought to blame domestic opponents of a no-deal Brexit for weakening his bargaining position in negotiations with the European Union, something he has called a “terrible collaboration.”
So Biarritz represents a complicated moment on the international stage for a politician who loves the limelight and is sure to try to use it, like all the other leaders, for his own political purposes.
“Boris Johnson understands political theater — he’s perhaps more into theater and communication than substance, so he will understand the importance of moral, emotional and verbal support from Trump while not wanting to alienate France and Germany,” Mr. Grant said.
This is new territory. For several decades the objective of British foreign policy has been to avoid choosing between Europe and the United States, acting instead as a bridge between the two.
But that option is fast receding because of the combination of Brexit and Mr. Trump’s disdain for the European Union, a bloc that he sees as an economic competitor.
Mr. Johnson’s tactic is to prepare energetically for a cliff-edge departure at the end of October, hoping that the prospective damage to European economies, especially Ireland, will force Brussels to reopen negotiations on withdrawal and drop the “backstop” designed to assure there is no hard border between Ireland and Northern Ireland, which remains a part of Britain, after Brexit.
But there is no sign of that yet. European leaders do not believe Mr. Johnson is as serious about a no-deal Brexit as he claims to be, are not sure he will survive long with a single-vote majority in any case and believe that it is Britain and Northern Ireland that would suffer most from crashing out, not the European Union.
European diplomats know that a majority in the British Parliament opposes a no-deal Brexit. They will also be loath to make concessions, analysts say, with speculation rife about an imminent election that could scramble British politics. And they remain adamant that Brussels will not sacrifice the interests of a member, Ireland, for those of a country that is heading out the door.
For his part, Mr. Johnson knows that any softening of his stance on Brexit would be seized on by the Brexit Party, led by Nigel Farage.
“I think it is a game of poker with two parties at the table, both with a strategy of not showing their cards,” said Joachim Fritz-Vannahme, a senior adviser at the Bertelsmann Stiftung, a research institute in Germany.
That means that the meetings in Berlin, Paris and Biarritz will be about message-sending at a critical moment in the European and British parliamentary timetable, said Mark Leonard, director of the European Council on Foreign Relations.
“London will see if Johnson gets anywhere with them, but if it’s a disaster and he gets slapped down on the backstop from Merkel and Macron it will have implications in the House of Commons and lead to more frenzied talks about votes of confidence,” Mr. Leonard said.
If Mr. Johnson wants to test the Europeans by threatening a no-deal Brexit, “this is also an opportunity for Macron and Merkel to deliver messages to the British political class,” Mr. Leonard said.
“Most European leaders do not believe that there is a parliamentary majority for a no-deal, so they may decide it’s worth being unyielding and see if the British Parliament does something in September.”
If some of Mr. Johnson’s advisers believe that the European side will cave in at the last moment, they are mistaken, Mr. Grant said.
“I really don’t think that the E.U. is going to move,” he said. “I don’t see why that would be in its interest, and why it would not be in its interests to stand up to Europe’s mini-Trump.”
Mr. Fritz-Vannahme said that Ms. Merkel would be polite and professional during the Berlin meeting. But he noted that two previous British prime ministers, David Cameron and Theresa May, also pleaded for Ms. Merkel’s help with their own European problems, only to go home disappointed.
All this leaves precious little time for any Brexit solution before Oct. 31 and, to complicate the picture, Europeans see Mr. Johnson as a difficult interlocutor.
A former journalist who pilloried the workings of Brussels, he was a leading pro-Brexit campaigner in the 2016 referendum and is regarded in continental Europe as Britain’s least successful recent foreign secretary when he held the post from 2016-18.
“He was known in all the other foreign ministries as unreliable and not on top of his dossiers,” said Mr. Fritz-Vannahme.
So, while there is still hope in continental Europe and it can chart a course to a smooth Brexit that retains close cooperation with Britain not just on trade but on security too, there is growing pessimism.
“We will all pay for Brexit, but we won’t pay as high a price as the British,” Mr. Fritz-Vannahme said. “We don’t have a discussion on the Continent about whether we will run out of medicines and gas.”