It makes absolutely no sense to do it any other way. Simply determine the total number of votes cast for each nominee and elect the individual who received the most amount of votes nationwide. Simple as that!
To do it any other way is to ignore the true will of the people. The decision is too important to be left to a few hundred individuals that are under no obligation to vote in line with their electorate. Not to mention the political games that are played by both parties when adjusting the electoral boundaries.