Brownback.
Huckabee as second choice.
Third, Thompson if he will really try for it, which I don't think he will. I don't think that he will campaign with the intensity required to win the presidency.
The Republicans don't have an electable selection, or none that appear so at this point. I don't like the Democrat alternatives but am expecting my next prez will be a Dem. Of those, Bill Richardson is the most palatable.
