When I see or read about Karl Rove, I think Alberich. Rove would be wonderful in the part. The voice of Alberich is not important. Rove lives the part. He is totally unloveable, and has apparently given up on attaining "love" (in his case "humanity") in order to attain power. His Tarnhelm is his position. He's got me plenty worried about the final music drama for us.
And, by the way, I've noticed a remarkable resemblance between Rove and Rush Limbaugh. Have they ever been seen in the same room at the same time??