But Higginbottom had a staunch defender on the Senate floor on Thursday in Sen. John KerryJohn Forbes KerryOvernight Defense: Pompeo clears Senate panel, on track for confirmation | Retired officers oppose Haspel for CIA director | Iran, Syria on agenda for Macron visit Senate must save itself by confirming Mike Pompeo Pompeo faces pivotal vote MORE (D-Mass.) who employed her as his legislative assistant and finally top policy aid from 1999 to 2007.

"In all those years on the hill, I want to assure my colleagues who are thinking about this position that she stood out not just for her policy knowledge and her understanding of the budget and the legislative process, but really for her ability to work across the aisle," he said.

Kerry said that despite the opposition from Republicans, Higginbottom would work across the aisle once in the position.

"I also saw first-hand her instinct to put aside ideology and to go after waste, to push for tough-minded budget reforms… all of which protected the taxpayers' interests," said Kerry.

Higginbottom will replace Rob Nabors, who is now serving as the White House's legislative director.  

Vicki Needham and Pete Kasperowicz contributed.