No one tries to win the popular vote. To win the popular vote would require a very different campaign strategy and therefore the popular vote is not a very good indicator of anything.

A good example is people like me who vote in a state that is solidly 1 way. I can vote by absentee ballot in NY, but I am not sure if I will because my vote is meaningless. Kerry is going to win NY by a large margin, therefore my vote whether for or against him is meaningless. Many people in states that are solidly 1 way (either Dem Or Rep) feel this way. For example, in the current system there is no incentive for the Republicans to bother to try get out the vote in NY, it is a waste of time and money. In a popular vote system (or a proportional allocation system) there would be a big incentive to get people out to vote and hopefully more people would vote.