Tonight outside the grocery store a man holding a clipboard approached me.
Him: Are you registered to vote?
Him: Would you be willing to sign a petition to get a third-party candidate onto the ballot?
Me: Quite likely -- which party?
Me: Oh good; I've been hoping a petition for Gary Johnson would cross my path. Gimme that.
Him: Sounds like you're politically active.
Me: If I were active I'd have my own petition.
Him: Sounds like you're politically informed.
Me: Yeah, that's closer.
Ballot access is rigged by the two major parties to, as much as possible, keep everybody else out. Other parties need to gather a disproportionate number of signatures, for each race, to get a candidate onto the ballot. And it's pretty much a given that the major parties will challenge the petitions for other candidates, so in practice you need to collect three or four times as many signatures as you officially "need", just to be safe. This is why I was very likely to sign the petition even before knowing who it was for (though if it had been someone repugnant I'd've said no).
Smaller parties are better served trying to gain local and state offices; the White House and probably Congress are out of reach. But there's more publicity to be had for national races, and this year especially I think it's worth giving serious consideration to alternatives. Gary Johnson is a pragmatist, not a hard-line idealist, and he has experience with the realities of the political world (he was governor of New Mexico). I hope we get more of a chance to passively hear what he has to say.
Added in a comment:
We need some form of preference ballot, yes, and since that's against the interests of those in power, it's not likely to happen. This is why other parties need to concentrate on smaller elections -- in a local election I think it's easier to campaign (a) at all and (b) on the merits of the individual candidate -- it's not just a party vote, but your neighbor Bob. (No, I don't have data; it seems reasonable but I could of course be wrong.)
The value of participating in larger elections isn't to get elected; that won't happen. The value is to be (potentially) able to influence the discourse. Isn't that why Sanders stayed in way past the point where he had to know that Clinton would be the nominee? He cares about getting certain issues front and center and used the primary to do that. If a candidate from another party can actually get into the debates (requires 15% in certain opinion polls; spread the word), can get some media attention, or can get people talking some other way, that helps even though he's not going to win. Most such candidates don't have, and can't raise, the enormous budgets needed for national races, though, and those with the massive budgets of course aren't inclined to let others in.
This year people are disgruntled enough that it feels like there could be an opening to get into the discourse. The odds are well against it, but it'd be nice to see it happen.