Do the candidate's statements really matter?

Citing my source, the ideas that follow are based off of skimming this article, from today's NY Times - http://www.nytimes.com/2004/10/26/politics/campaign/26BUMI.html?oref=login

The article, which is very good, cites the fact that you cannot expect that the candidates can keep with their pledges, as a President's agenda is often dictated to him by outside forces. Based on that - what do we use to judge who to vote for?

Obviously, party ID is huge - a large plurality of voters vote for a party because their parents did, or their faith base told them too, or their spouse has a strong preference in the matter. But their is also a large plurality of voters who base the decision on the candidate, not the party. So what do these people decide upon, if not the plan that each candidate outlines?

Here is my theory - when a candidate starts talking, people zone out after a few minutes and then perk up at the end. They don't really hear the nuance of the position - hence the success of the Bush campaign in 2000 and 2004 keeping messages simple and succinct. But even then, if the message is irrelevant, based on the premise that outside influences determine the course of a presidency, what now? The answer - non-verbals. How a candidate looks, reacts, speaks, how a candidate feels to the voter. It's a scary thought, but people react much more, in my mind, to the perception of the candidate - Bush as the Cowboy, Kerry as the War veteran - than to anything that comes out of their mouth.

Feel free to argue. I'm probably wrong. It's an interesting topic nonetheless.