Former Vice President Joe Biden won't reveal his short list for VP candidates, but whoever it is will have to be able to "immediately" take over in the event the 78-year-old politician dies while in office.

"For me, it has to be demonstrated that whomever I pick, there’s two things: One, he’s capable of immediately being a president because I’m an old guy."

Biden quickly added that he's "in great health" due to his morning workout routine (which allows him to call voters 'fat' and challenge them to pushup contests), but then said "you never know... you never know what's going on."

Biden talks about @KamalaHarris as VP. Says most important criteria is knowing whether the woman or man can do the job ‘ because I’m an old guy.’ pic.twitter.com/Zycm4Z4ywh — Cleve R. Wootson Jr. (@CleveWootson) January 29, 2020

As the Daily Caller's Chuck Ross notes, "Biden has insisted throughout the campaign that his age should improve his electability."

"Look, one of the reasons I’m running is because of my age and my experience," Biden said during a debate on Oct. 15.

"With it comes wisdom," he continued. "We need someone to take office this time around who on day one can stand on the world stage, command the respect of world leaders from Putin to our allies, and know exactly what has to be done to get this country back on track" (via the Daily Caller).

Biden has been dogged by concerns about his age throughout the campaign. His chief critics have pointed to his repeated gaffes on the campaign trail, and several speeches where he misidentified cities and states, or mixed up decades when certain events occurred. Rep. Alexandra Ocasio-Cortez questioned whether Biden’s age had anything to do with his poor debate performances over the summer. “His [Biden’s] performance on the stage kind of raised some questions with respect to [his age],” the New York Democrat said in an interview in July. -Daily Caller

Yet - despite Biden's age, documented gropings, racism, creepy leg hair stories involving children, telling 10-year-old girls they're good looking, and snapping at voters - he's still the 2020 Democratic front runner.