“I hope there’s an age limit,” he joked, without mentioning that Democratic candidates Joe Biden and Bernie Sanders would turn 80 in office if elected.
The Democratic candidate also explained why Trump "is truly a terrible president. Not just bad, terrible."
The "Last Week Tonight" comedian mocked the Democratic contender's chances against Donald Trump after his outdated remarks.
The Democratic presidential hopeful shot down a question about the former vice president's fitness for office.
Twitter critics are suspicious about the 1962 incident involving the “Romans” gang leader that Biden insists threatened him at a swimming pool.
"The American people have the right to know about whether the person they are going to be voting for ... is healthy," said the Vermont senator.
The former vice president's mental acuity has been called into question by some Democratic presidential rivals.
The former housing secretary questioned whether Biden was able to recall the facts of his health care plan during the third Democratic debate.
Biden can't seem to shake questions about his consistency and whispers about his fitness for office.
CNN's Chris Cuomo said Castro's attack on Joe Biden "seemed like a cheap shot."
Trevor Noah, Stephen Colbert, Jimmy Kimmel and others all highlighted the funniest parts of the debate.
Former Housing Secretary Julián Castro chided the former vice president during the debate in Houston, an attack Booker said came from "legitimate concerns."
The former vice president ignored the issue of reparations and instead talked about teacher pay and how families raise kids.
The much-anticipated confrontation between leading 2020 candidates Joe Biden, Elizabeth Warren and Bernie Sanders never really came to fruition.
The former housing secretary did not hold back against former Vice President Joe Biden at the Democratic presidential debate in Houston.
The Univision journalist did not let candidates evade questions on their immigration record at Thursday's debate.
The ABC News debate is the first limited to one night after several candidates dropped out and others failed to meet new qualification standards.