why do you keep talking like you have some secret info that i dont know about
there are all kinds of factors that effect the vote, base is one of them, and so is level of enthusiasm, so is the economy, and there are other factors like likability, and the party in power
if you make your prediction based on the base, thats fine, you have a very simple analysis based on what you believe is the base, my analysis is more sophisticated and takes more factors into account
but at the end of the day all you can do is bump this next November and see which model is correct