The Senate is expected to vote Wednesday on Tulsi Gabbard's confirmation for director of national intelligence, after her nomination survived a crucial committee vote last week and cleared a key procedural hurdle Monday.

A source with knowledge of the proceedings told ABC News that newly confirmed CIA Director John Ratcliffe, former NSA adviser Robert O'Brien and former Sen. Richard Burr, a former Senate Intelligence Committee chairman, have been making calls to senators on Gabbard's behalf. Gabbard has also talked to senators since her hearing, a source said.