Among Bolton's most vocal supporters are senior administration officials loyal to Flynn and who are upset at the general's firing. Multiple sources described an effort by these Flynn loyalists to ensure that Bolton is selected as his replacement.
The selection of Bolton as the next national security adviser would empower Flynn's allies still in the White House and send a message that his national security vision is represented within the Trump administration. Bolton is also favored by White House staffers who are opposed to the selection of any candidate who criticized President Trump during the 2016 campaign.
President Donald Trump has not settled on a final selection yet and is also eyeing retired Army Gen. Keith Kellogg, who has been acting national security adviser since Flynn's departure, as well as other candidates.
"There's a strong inclination in the NSC towards the kind of experienced leadership Bolton would represent," said one current official, who requested anonymity to speak freely about the situation. "He knows the ins and outs of D.C. but he's not an establishment, Never Trump type. There's also a lot of respect for General Kellogg and KT McFarland, both of whom have really stepped up under challenging circumstances."