Barack Obama and Joe Biden's close friendship has included moments of tension.White House/Pete SouzaBarack Obama and Joe Biden's "bromance" is widely celebrated, but their relationship is complex.Tensions simmered when Obama favored Hillary Clinton over Biden in the 2016 election.Obama reportedly expressed doubts about Biden's ability to win in 2024 after his disastrous debate.Former President Barack Obama and President Joe Biden's close friendship became a widely celebrated "bromance" during the Obama White House years.While the two share a close bond, their political relationship has also included disagreements and periods of tension, especially amid Biden's decision to drop out of the 2024 presidential race.Here's a look inside Obama and Biden's close yet complex friendship.Joe Biden and Barack Obama briefly ran against each other in the 2008 Democratic primariesJoe Biden and Barack Obama during a Democratic primary debate.Justin Sullivan/Getty ImagesDuring his campaign, Biden garnered criticism for describing Obama as "the first mainstream African-American who is articulate and bright and clean and a nice-looking guy" in a 2007 interview with the New York Observer.