David Steinberg makes an interesting point about how to interpret polls that ask a person's party affiliation. The usual way is to consider political views to be arranged along a line, with those who answer Republican on the right, those who answer Democrat on the left, and those who answer independent in the middle. But why is this so? Do the two major parties encompass all people to the extreme left and right? Certainly not. If a Republican becomes more moderate, he or she will lose people to the right, just as a moderate Democrat looses people to the left. Thus, there are independents to the left of Democrats and to the right of Republicans.
The poll questions would be more illuminating if they had a richer notion of what it means to be independent.