President Joe Biden is 80 and Donald Trump is 77, and they are prone to making gaffes. But polls show that voters view age as more of a liability for Biden than they do for Trump. An August poll from The Associated Press-NORC Center for Public Affairs Research found that 77% of U.S. adults viewed Democrat Biden as too old to be effective for four more years. The same poll found 51% of adults said Republican Trump is too old. A professor who studies the characteristics of elected leaders says that such perceptions are tied to different expectations for each man and that Trump's supporters have shown a willingness to overlook more significant flaws.