I am guaranteed failure only if I don't try. Success is also dependent on how you define it. I realize the mountain I will have to climb, I realize my chances of actually getting elected. Getting elected is not my first and primary goal, it is secondary, but I do mean to win.
Like rain drops on a pond, concentric circles emanating, I can have an impact on the discussion, I can impact the people around me. If there are enough rain drops, we can change things. One cannot expect to change the world, without first changing themselves. This means we must get out of our easy chairs, and put our words to action, in any and every way we can. Each must do that which he/she can.
Talking at people who agree with us accomplishes nothing. Those who disagree with us are not going to knock on our doors, we must find them wherever we can. There are a million reasons to rationalize that we won't be successful or make a difference. I am an optimist, I will do what I can. I strongly encourage everyone else to do what they can.
We are not powerless.