Was Warren the strongest potential Democrat on par with Biden this year?

[Mr. Morden]

No. I doubt anyone but a hypothetical third Obama run could have prevented her nomination this year.

I thought we were talking about who would be strongest in the general election, not the primary?  Clinton may well have been a lock over any rival for the nomination.  But I'd say it's an open question as to whether, should she have declined to run and someone else been nominated, that other nominee would have a better chance against Trump than she does IRL.