Well it probably won't, right? I too find this hard to reason about, whether regarding voting or cigarettes. Perhaps I'm just thick. Is there a concept in, say, game theory that deals with this?
I think an argument can be made that smoking another cigarette today will increase the odds of you smoking another cigarette tomorrow (And the day after, and so on) - which could a large effect on your health.
timeless decision theory: if you decide to smoke a cigarette in this situation it is likely that you will decide to smoke a cigarette in all similar situations.
Alas, the same cannot be said for voting.