A Shabbat-observant Jew will take over as chief of staff to President Barack Obama.
Jack Lew, who previously worked for President Clinton, has been named as the successor to William Daley.
Mr Lew, 56, is President Obama's second Jewish chief of staff. Until October 2010 he was served by Rahm Emanuel, but the combative son of a onetime Irgun fighter stepped down to run – successfully – as mayor of Chicago.
It is not Mr Lew's first role in the Obama administration; he was deputy secretary of state from 2009-2010 and since has been working as budget director, the same position he held under President Clinton.
Seen as an expert in Washington politics, Mr Lew's insider knowledge has been welcomed as a contrast to Mr Daley, whose background was state politics rather than the federal government.
Mr Lew, the son of a Polish immigrant to New York, is well-known for his refusal to work on Shabbat. However, according to Washington lore, President Clinton once called his answer-phone on a Saturday urging Mr Lew to respond. The devout politician consulted his rabbi, who gave him his blessing to answer urgent calls from the president.