If "safe" is your main concern, forget about Biden. The safest bet to beat Trump would be Klobuchar,

[FBaggins]

37. I'm afraid your notion of "safe" is unsupportable

You've listed a bunch of reasons to like her... and even to vote for her... but they don't add up to her being a "safe" candidate (if indeed that's what we're looking for).

Not sure I agree that we should be looking for "safest" when Trump looks so beatable. But if that's what we're looking for than Biden (like Gore before him) is the poster child for "safe". Eight successful years in the White House and two national elections with his name on the ticket. If there were skeletons in his closet you would expect to know about them by now. "Experience" out the wazoo. Unbeatable name recognition.

We could go on and on. In fact, it could be plausibly argued that the whole reason that he's the clear frontrunner at this point is because the party views him as the safe candidate.