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These days, Ron Klain, President Biden's influential chief of staff, is often viewed as a "surrogate" for Biden himself, The New York Times reports. But like any other longtime working relationship, theirs has not been without its rough spots.

In 2015, Klain — who also served as Biden's chief of staff during his time as vice president — signed on to work for Hillary Clinton's presidential campaign without waiting "until [Biden] announced he was not running," the Times writes. The move was viewed as a "breach of the Biden loyalty protocol and became a sore spot in the vice president's ecosystem," particularly with Jill Biden. 

In a 2015 email to John Podesta, Clinton's campaign chairman, Klain wrote, "It's been a little hard for me to play such a role in the Biden demise — and I am definitely dead to them," per the Times. 

But, thankfully, time heals all wounds, and Klain is back in the White House advising Biden just like before. Read more at The New York Times.