Over the past 20 years voting patterns in most states have stabilised, with fairly predictable results, reducing the weight of small states and even some larger ones.
Just a few large states, known as swing states, have hung in the balance. These "swing states", such as Florida or Ohio, thus become crucial battlegrounds.
In the past two elections, for example, candidates paid much more attention to campaigning in Florida than in New York, which was considered an obvious win for the Democrats, or in Texas, which was considered to be in the Republican camp.
Some political pundits are predicting, however, that the election this time may move these established goalposts. And this is forcing the candidates of both major parties to reinvent campaign strategy.
Critics say that the system is out of date, that in a modern democracy only the popular vote should count. Others say that the importance of the large swing states has become so great, that the original intention of the constitution to give a voice to the less populated states no longer holds.
Defenders of the Electoral College say that if it were to be eliminated, candidates would only campaign in the large urban centres, disregarding the rural vote entirely.
There is no consensus on whether the Electoral College should be abolished in favour of a direct vote.
Every election year the topic of reform comes to the surface. But one of the obstacles to any change is the difficulty with which the constitution can be amended.
In keeping with the constitution's intention to divide power between the states and the central government, a constitutional amendment has to wend its way through both the federal and the state systems, getting the support of two-thirds of both houses of the US Congress plus three-quarters of the state legislatures or special conventions.