President Obama has "privately expressed grave concerns" about Biden's run for the White House, according to a stunning new report from Politico. Obama reportedly said of Biden: 

"Don't underestimate Joe's ability to f–k things up."

Despite the endorsement and the former Obama administration painting a rosy picture of the relationship between the two, the Post describes their relationship as being "fraught with tension".

Former White House communications director Jen Psaki commented of their relationship:

 "You could certainly see technocratic eye-rolling at times." 

The attitude reportedly is what led Obama to endorse Hillary Clinton, instead of Joe Biden, in the 2016 Presidential race. 

"The president was not encouraging," Biden said of Obama's support in 2016.