This is actually a loaded question. Are we talking about just on the presidential level, the state level, or both? Even deep "red" states have been known to elect Democrats for governor and other statewide offices.
Also, you can define the question in a historical sense, or strictly in the contemporary sense. In the former, I think freepcrusher is correct and Kansas is the best answer. In the latter, I would lean toward the sparsely populated western states of Utah, Wyoming, or Idaho.
True. But a lot of supposedly "blue" States have elected Democrats to statewide offices too.
