And thus is the paradox of religion and faith. Parts of the Bible can be interpreted to say that since God is all knowing and all seeing, He knows what you will do, think, or say before you do. Other parts can be interpreted to mean that all things move through God and all things are done according to his will.
Together these can be interpreted to mean that nothing you or I do will matter in the end, because it is all pre-destined. Or at the very least, what we THINK is free will is merely a chess move in God's pre-measured plan.
I prefer to think of God as being laissez faire with regard to the activities of man, with a firm grasp of the measure at time of judgement. Think about it.....if God has pre-ordained our every thought, breath, and action, what is there to judge on judgement day? So if you believe there is a judgement at the end of earthly life, than you by derivation believe that your actions matter. And if voting as an act you can choose to pursue or not pursue, than the outcome of your engagement in this activity is most likely not pre-determined.
In short.....vote.