Motivation: selfish greed, IMHO. I think, in part, it's because he gets appointed to head choice committees....as you know, those who are in longest not only get put on better committees, they get named as chair.....if South Dakota picks a new senator, that senator has little to no chance of getting placed on important committees or to be chair of anything. What I don't understand is why so many South Dakotans actually believe it's better to have an obstructionist elected...surely they can't all be liberals in South Dakota. If the majority is not liberal, then the conservatives of that state receive but mere crumbs by electing Daschle.