A good politician (and I realize that is an oxymoron), er, let's say an effective politician will ignore all the polls showing him/her in the lead. Remember President Dewey?
I think these public polls serve only to spark these kinds of debates, and drive people to their websites, newspapers and TV programs, so they can charge higher advertising rates. The candidates have their own internal polls that guide them. If they pay attention to these, they are fools.