Former Defense Secretary Robert Gates told CBS News that age is a “problematic” issue in the 2020 presidential election.

Gates said candidates in their late seventies — like former Vice President Joe Biden, who is 76, and Sen. Bernie Sanders, who is 77 — don’t have the “kind of energy that I think is required to be president.” He also said he believes President Trump, at 72, may also be too old for the job.

Gates added: “I’m not sure you have the intellectual acuity that you might have had in your 60s. The thought of taking on those responsibilities at this point in my life would be pretty daunting.”

Washington Post: “Only one of the 21 Democrats running for president wants voters to see him as the establishment choice best able to fulfill the promise of President Barack Obama’s third term. But former vice president Joe Biden has yet to become a consensus pick of the White House and campaign advisers who made Obama’s two terms possible.”

“With some exceptions, the generation that brought to Washington an insurgent message they called ‘hope and change’ is once again resisting pressure to get in line, as they scan the field for a possible heir to Obama’s transformational 2008 candidacy and worry about a repeat of the disastrous 2016 election.”

“Many others, however, speak of their continued hunger for a new generation of leadership and a fresh face who can transcend political divisions. They worry about siding with a lifelong Washington fixture. And they are eager for someone like Obama who can bring new voters to the polls.”