“a single grain of rice can tip the scale. one man may be the difference in victory and defeat” what does this mean

If one person chooses to vote on an opposite side, that election could have a bad person as a winner which could affect how the government runs. Even though it’s one person, it makes a difference. If one more man had fought during the civil war, the south could’ve won. We could still have slavery. Image how corrupt of a government the United States would have