I ordinarily like American Atheists, but if reports are true (I don't really enjoy watching videos, and I haven't found a transcript yet), Ellen Johnson of American Atheists is full of shit when she exhorts atheists to stay home on election day.
Now I completely understand her frustration that atheists' interests are not adequately represented in today's government. But just on pure pragmatism, not voting will diminish, not enhance, whatever political power atheists actually have. (The typical atheist's aversion to bloc voting makes direct political power difficult to exercise.) Both of the leading Democratic candidates are adequate on church-state separation; just on that single issue, it's not too difficult to justify voting for either.
More importantly, voting, win or lose, legitimatizes democracy itself. There is no democracy without voting. If you want a democracy, you have to vote. Even if it were Mike Huckabee vs. William Jennings Bryan in the general, you still have to vote. Vote Green. Vote Libertarian. Write in your brother-in-law. But vote.
I should get off my ass and actually become a paying member of American Atheists so I can vote this dumbass out.