Two top aides depart Obama's White House

Washington (CNN)The White House announced the parallel departures of two top aides to President Barack Obama on Wednesday, just past the midway mark of Obama's final term.

Dan Pfeiffer, one of the President's longest-serving strategists and closest advisers, will depart the White House in early March, officials said. The second adviser, communications director Jennifer Palmieri, will leave in the spring. A Democratic source said she'll fill the same role on Hillary Clinton's all-but-certain presidential campaign.
Pfeiffer and Palmieri will leave major vacancies in the West Wing as Obama looks to buck the notion he's entering his lame-duck phase. Having set an ambitious agenda focused on the middle class, Obama will now need to recruit new staffers willing to come on board with only two years remaining in his presidency.
    "While their departures are significant, there is indeed value in bringing in new, energized staff with fresh ideas and new perspectives," a White House official said, noting Palmieri and Pfeiffer had made their decisions to leave independent from one another.
    "Instead of filling jobs as one-offs, this timing presents an opportunity to build a cohesive team that is expressly designed to achieve and implement the President's priorities for the fourth quarter of his presidency," the official said.
    Pfeiffer is one of the longest-serving Obama staffers, with ties to the President's first presidential campaign in 2008. A previous White House communications director, Pfeiffer currently serves as assistant to the President and senior adviser -- a role he's used to hone the administration's messaging in a shifting media environment.
    "Dan has been beside me on every step of this incredible journey, starting with those earliest days of the campaign in 2007," Obama said in a statement on Wednesday. "And through it all, he's been smart, steady, tireless and true to the values we started with."
    An official at the White House said Pfeiffer, who'd been contemplating leaving the administration for a "long time," told Obama the day after this year's State of the Union address that he'd made his decision to depart.
    "Given the position of strength we are in right now ... he is now comfortable moving on," the official said.
    Palmieri -- who also served in former President Bill Clinton's administration -- is expected to assume a role on Hillary Clinton's campaign for the Democratic presidential nomination, should she decide to make a run. Two sources familiar with the campaign's planning said Palmieri was likely to take on the top communications job.
    She'll join another former Obama adviser, John Podesta, who is also expected to assume a major role on Clinton's campaign, potentially as its chairman. A top aide who helmed the administration's efforts combating climate change, Podesa is slated to leave the White House this month.
    As one of Pfeiffer's final tasks at the White House, he's been reviewing how the communications staff engages in a social media-driven news environment. The White House official said Pfeiffer had traveled to Silicon Valley recently to garner recommendations from American tech firms on how best to engage audiences using their platforms.
    The evidence of those efforts were on display last month leading up to Obama's annual State of the Union address: key elements of the speech were unveiled ahead of time on Facebook and Twitter, and the entire text of the speech was published on the website Medium before Obama stepped to the podium.
    In an interview on CNN's "Reliable Sources" in December, Pfeiffer said his White House position "has been the greatest job I've ever had."
    He acknowledged "there will be a day when it makes sense for me to do something else," but said he hadn't made up his mind about what's next.
    "I think when I leave the White House, whenever that will be, I will spend a significant amount of time on a beach with an adult beverage for a long time," he said with a laugh. "And then figure out what the next chapter is."
    In December, Pfeiffer spoke animatedly about American media being "on the cusp of a massively disruptive revolution."
    "There are big things that are going to happen," he said. "The old models are starting to fall. And how we adjust to them, and how everyone adjusts to them -- you know, entertainment television, the movies, the news, politicians and the government trying to get their message out -- is going to be a massively fascinating thing."
    Pfeiffer added that he thinks these changes are "even more interesting and potentially consequential than the invention of television and the invention of the Internet, because it's all those things combined at the same time."
    Pfeiffer's departure leaves few remaining "Obama originals" -- those trusted aides and advisers who helped Obama win the White House and navigate the early years of his presidency. Valerie Jarrett and Anita Decker Breckenridge, both senior advisers who have served Obama for years, are two trusted aides who will remain in the West Wing.
    Others, however, have moved on: David Axelrod, David Plouffe and Alyssa Mastromonaco, three former senior advisers who served on Obama's 2008 campaign, have all left government for now.
    Obama said Wednesday that Pfeiffer had served not only as a top aide but as a friend.
    "I'm going to miss having him just down the hall from me," he said.