When evening draws near on a Friday night, President Barack Obama makes sure that his Chief of Staff, Jack Lew, knows it is time for him to get home for Shabbat.

Mr Obama respects the balance that a Sabbath-observant Jew needs to have, and this balance, along with Mr Lew’s understated alacrity, has allowed the son of Polish Jewish immigrants from Queens in New York City to reach unprecedented heights of government.

Mr Lew — also formerly director of the Office of Management and Budget, a position he also held in the Clinton administration — is now the president’s nomination to succeed Tim Geithner at the Department of the Treasury. And if — as is highly likely — he is sworn into the office of Secretary of the Treasury, Mr Lew will become the first Orthodox Jew to hold a national cabinet post in America.

The man whose strikingly loopy signature is set to appear on all US banknotes would also have a profound influence over the global economy.