> Even if it did increase the probability of an Obama win, or even if it did have no effect on the election outcome, why would it be a wasted vote?
If you think Obama is substantially worse than Romney and it increased the probability of an Obama win, its not a wasted vote, its a counterproductive vote. (That is, its a worse that decreases the expected realized utility.)
> What you're effectively doing is raising publicity for the cause.
There's better ways to do that that precede the voting booth, and which, if successful, eliminate the problem of counterproductive voting. At the voting booth, when those prior efforts haven't succeeded, you have to weigh the benefits of maybe microscopically advancing the PR for the cause by adding one to the count of protest votes against the microscopic possibility (times the expected magnitude of harm) of tossing the election to the least-favored of the major party candidate, and the policy consequences of that (which can, depending on the candidates choices, include a greater decrease in the long-term prospects of the kind of changes you want than the increase that would be expected from the PR value of a third-party vote, particularly if you think the major-party choices are between "basically maintaining the status quo" and "maintaining the worst features of the status quo while substantial reducing economic and political freedoms".)
Political engagement isn't limited to voting.
