Donald Trump hosts Germany's Angela Merkel at the White House on 17 March, a meeting delayed by a snowstorm and still clouded by a storm of words between the two ostensible allies.
The cautious German chancellor and the impulsive US president will hold talks in the Oval Office, hoping to narrow differences on NATO, Russia, global trade and a host of other issues.
Talks had been scheduled for Tuesday, before a blizzard in the eastern United States intervened and delayed the likely difficult meeting.
For years Merkel -- a trained physicist -- had been president Barack Obama's closest international partner, with the two sharing a strong rapport and a similar deliberative approach.
With Trump, Merkel may settle for avoiding an open argument or a 140-character Twitter missive.
Before coming to office the US president called Merkel's acceptance of refugees a "catastrophic mistake" and said she was "ruining Germany."
He also demanded countries like Germany step up defense spending, a sensitive issue for a nation that has had a strong pacifist tradition since World War II and proselytizes fiscal prudence.
In a similar vein, Merkel has sought to remind the real estate mogul of democratic values.
Any "close cooperation," she said, must be on the basis of the "values of democracy, freedom, respect for the rule of law and human dignity, regardless of origin, skin color, religion, gender, sexual orientation or political belief."
Comments like that have prompted some of Trump's fiercest critics to declare Merkel the new "leader of the free world," a moniker normally taken up by the occupant of the White House.
Between meetings the pair will hold a joint press conference that is sure to dredge up past barbed disagreements.
"Germany looks toward Washington with a mixture of vulnerability and confidence," said Jeffrey Rathke of the Center for Strategic and International Studies.
"Germany is the de facto leader of the European Union, but the Union is undergoing internal and external trials that make its future uncertain," he added.