"If you go into the early stages with a national lead and get bumped off or do poorly in the early states, that usually means you're done," Hume said on "The Story with Martha MacCallum." "So Biden has a lot to worry about."
The former vice president has been on the defensive in the past few weeks after a series of public misstatements and gaffes, with some questioning whether he has the stamina to stay in the race.
Hume said he believes Biden is experiencing what many older men experience with age, but added the stumbles are clearly impacting the campaign.
"In more recent times you're beginning to see signs that he's ... making mistakes because his memory is failing him," Hume said.
Discussing why Biden is running for president, Hume said he believes the former senator from Delaware has always wanted the job.
"I think he's always wanted to be president. And I think he's always kind of thought that, you know, his moment would come and he would loyally serve eight years under Barack Obama as vice president and, you know, [he] never really stepped out of line," Hume said.
"I think he feels like ... after all he's been through at least he ought to get the presidency."