Former vice president Joe Biden has reportedly suggested that he would only serve one term if elected president but has stopped short of publicly pledging not to run again.“If Biden is elected, he’s going to be 82 years old in four years and he won’t be running for reelection.” a Biden campaign adviser told Politico, arguing that the former vice president could serve as a "good transition figure" to defeat Trump and usher in the "next generation of leaders."“He’s going into this thinking, ‘I want to find a running mate I can turn things over to after four years but if that’s not possible or doesn’t happen then I’ll run for re-election.’ But he’s not going to publicly make a one term pledge,” another senior Biden adviser said.Democrats have raised concerns about Biden's advancing age, noting that he will be 82 in four years. The more progressive wing of the party has also been cool towards Biden, saying he does not represent the new leftward direction of the party. However, critics of the notion of making a one-term pledge have said Biden would do himself a disservice and damage his presidential power by doing so.Biden responded "no" in April when asked whether he would serve only one term, but in recent months has hedged more on the issue.“I feel good and all I can say is, watch me, you’ll see,” Biden told the Associated Press in October. “It doesn’t mean I would run a second term. I’m not going to make that judgment at this moment.”The former vice president continues to outpace his Democratic primary rivals, polling at 28 percent, more than 10 points ahead of Senator Bernie Sanders's 17 percent, according to the Real Clear Politics average of polls on Wednesday.