What exactly is the role of a first daughter? That question in Berlin this week had Ivanka Trump fumbling for a reply. Without having ever won a vote, Donald Trump’s elder daughter is now among the world’s most influential people. Her husband, Jared Kushner, is the Trump administration’s plenipotentiary by virtue of his marriage. Both appear to be nice people: friends describe them as “normal”. But their ascent to the pinnacle of US power has no parallel in modern western democracy. The Germans are not alone in wondering what to make of it.

From China’s Xi Jinping, to Canada’s Justin Trudeau, and Germany’s Angela Merkel, world leaders are working on the assumption that Mr Trump will keep his daughter and son-in-law in key positions. Others, such as Nikki Haley, US ambassador to the UN, “can easily be replaced”, as Mr Trump quipped this week. But foreign governments think the president’s close relatives cannot be dislodged. They may prefer it that way. Ms Trump was apparently critical in drawing her father’s attention to the human effects of Syria’s recent chemical weapons attack. Her husband is busy sidelining Stephen Bannon, chief proponent of the “America first” doctrine. The couple acts as a curb on the president’s stronger impulses.

Ms Trump also serves to humanise her father. This week she co-wrote an opinion piece for the Financial Times with Jim Yong Kim, president of the World Bank, to argue for a greater role for women in the global workforce. Following a campaign in which her father made a priority of restoring male-dominated jobs, such as coal mining, Ms Trump plays a useful yin to her father’s yang. It is no accident that Ivanka was the first Trump to make a high profile foreign visit since her father’s inauguration. Mr Trump has still not travelled abroad.