Of course it is. I and my wife vote for Bush. Bush wins by one vote. We don't vote, Bush loses by one vote to Gore. Not voting resulted a Gore win, same result as if we had voted for him.
You’re assuming we have only three choices. Dem, Rep., or none.
I’m waiting for more choices to emerge. In any case, I don’t vote for liberals.
The absence of votes on one side of the tally does not increase the number of ballots cast on the other... unless you are doing "million mom", "million man" or democrat math.
For example:
Obama gets 40,000,000 votes.
I do not vote for McCain.
Obama still gets 40,000,000 votes.
My not voting for McCain did not result in Obama getting 40,000,001 votes, therefore, it was not a vote for Obama.
See how simple arithmetic really is?