Longtime Mormonfag here.
I would like to point out that there is a difference here. Mitt Romney is not a higher up in the LDS church. He's just a regular member. The higher ups are not corrupt in the LDS church.
I will say we have a terrible track record in politicians, but again remember that most politicians today do not get into office without something on them or can be blackmailed and controlled. I feel the few LDS in politics have to have been blackmailed into what they are doing. It just goes against LDS culture otherwise.