I can't prove a negative but consider that winning the Democratic primary requires convincing a bunch of left-of-center voters to support your plan.

Sanders couldn't do that. How do you think he would have fared with Republicans?

He's never passed a significant bill of his own and focuses on renaming post offices.

The man has no political skill. As president he would have been a disaster.

> The man has no political skill

This is what I take issue with. It's a heavy enough accusation that it needs receipts. It needs proper framing on why exactly the benchmarks you've listed are important for delineating political skill and why other benchmarks are not.