(CNN) Deputy White House Chief of Staff Rick Dearborn will leave the administration early next year, CNN has learned, and is expected to pursue work in the private sector. His departure has been rumored for weeks, and sources familiar with the matter say he has been privately telling his West Wing colleagues that he would likely leave soon.
Dearborn had a wide portfolio in the White House and oversaw its political operation, public outreach and legislative affairs. He saw the passage of the sweeping Republican tax bill as his time to leave, sources familiar with his move tell CNN.
His exit comes as the White House is steeling itself for a string of departures once President Donald Trump hits the one-year mark in office. It was reported earlier this month that Dina Powell, the deputy national security adviser, is also expected to leave. The Wall Street Journal was the first to report on Dearborn's departure.
Dearborn's departure also highlights how Jeff Sessions' influence has dwindled in the White House. Before he was named attorney general, several of Sessions' top aides, including Dearborn, left his Senate office to go work for the Trump campaign, and eventually the White House. With Dearborn's departure, most have either left or become Trump loyalists.
Though Dearborn is from Oklahoma, he has deep ties to Alabama. He has personally known Sessions for decades, and served as his chief of staff in the Senate for several years. In the weeks leading up to the special Alabama Senate runoff, it was Dearborn who acted as a liaison between Sen. Luther Strange's campaign and Trump, though he initially encouraged Trump to stay out of the race.
After Trump initially endorsed Strange in the runoff, he was shown polling in late August that predicted Roy Moore would defeat Strange by a significant margin, sources familiar told CNN. Trump weighed turning his attention away from the race, the sources said, and at that time, there was no specific plan for him to visit the state to rally support for Strange.
Before making a final decision, Trump consulted with Dearborn to further explore Strange's chances. It was Dearborn who then got in touch with Strange's campaign after speaking with the President. A source familiar with the conversation said the campaign implored Dearborn for the President's full endorsement -- reminding him of Strange's commitment to Trump's agenda on immigration and the budget, and arguing that a Senator Moore could be a White House nuisance. They also played up how both Trump and Strange are newcomers to politics.
After Moore defeated Strange by several points, Trump was infuriated, and sources said he felt misled by Senate Majority Leader Mitch McConnell and his political team, who encouraged him to endorse and campaign for Strange.