WATFORD, England (AP) — British Prime Minister Boris Johnson is juggling election campaigning with hosting a meeting of NATO leaders, including an unpredictable U.S. President Donald Trump.

Johnson is appealing for unity in the fractious 29-nation military alliance, saying Wednesday that “If NATO has a motto, it is: One for all, and all for one.”

Fissures were on display as the two-day NATO gathering began Tuesday, as Trump and French President Emmanuel Macron sparred over Macron’s criticism of NATO and Turkey’s military operation in northern Syria.

The visit by Trump, who is widely unpopular in Britain, could complicate campaigning for the country’s Dec. 12 election. Johnson wants to avoid being too closely associated with the U.S. leader and was not photographed alongside Trump Tuesday, though the two met in private at 10 Downing St.