He's probably a bit dumber than Soros/Clinton/McAuliffe hoped. But as long as he sticks to the big lie tactics he can get traction.
On a positive note, his backers were probably not concerned enough to dig into Clark's past. Acxiom. Kosovo. Messer Griesheim.
FYI, I think buddies Sweeney and Soros are positioning forces to engineer an AFL-CIO endorsement for Clark.