The variable literary craftsmanship of Barack Obama

For some strange reason, the literary gifts Barack Obama showed in his two autobiographies are nowhere in evidence in his op-ed yesterday in the WaPo. Kevin Williamson notes the poor quality of writing in the op-ed.

Isn't it odd that a literary master could have such different skill levels? Some may deduce he used a ghostwriter for the WaPo. Or could he have used a ghostwriter elsewhere?

Hat tip: D.M. Giangreco