Best suggestion I saw was Lox's that you could only get elected if you got more than 50% of the vote. Though I'd advise that you made it at least 50% of the people entitled to vote. Some countries have that kind of rule.

Maybe as a compromise they could make it that the fella elected has his or her salary and pension tied to the proportion of the total electorate that votes for her or him. Except that I suppose the salary and pension aren't a very important part of the financial rewards of the job. Who was the last President (etc etc) who left office poorer than when they came in?