I'm resisting the urge to comment on the presidential election as best I can, but this post by Hunter at Daily Kos is sensible and eloquent:
You may note, readers, that I have little patience for the premise that both parties are equally crooked and that We Might As Well Stay Home, or however it is being phrased in any of its particular election incarnations, and so have little patience for Jill Stein's pitch to Sanders supporters this go-around. We have already put this theory to the test, after all: We were told it would make no difference whether we elected a not-progressive-enough lifelong politician or his counterpart, an overprivileged idiot man-child with a middling business record and no intellectual curiosity whatsoever. We tested the premise, and came away with smoking holes in the ground, wars, worldwide instability, nuclear proliferation, massive deficits, and a global recession.
So, apparently, there is at least a little difference in results depending on whether you elect a not-progressive-enough, too-corporate-connected lifelong politician or an overprivileged idiot man-child spouting gibberish. There are not many opportunities to test political theories in real life, but we have tested this precise one using the entire collected resources of the nation, and been uniquely privy to the results.
There may once have been a time when it was true that there was insufficient difference between the parties to vote for either. It has not been true in my lifetime, however. When one party is proudly implementing voting restrictions against minorities, you are obligated to not merely ignore them, but defeat them. When one party is proposing an ethnic minority be scrutinized, rounded up, and shipped from the country en masse due to the "danger" they pose, you are obligated not merely to snuffle your theoretical disapproval, but to stop them. If you value a supposed American tradition of freedom of religion but suppose that the asked-for closing of the border to members of one particular religion would be an acceptable risk, so long as your own conscience is not sullied by having to vote for someone you don’t like very much either, you clearly believe your conscience to be worth more than other people's children.
You are proudly declaring that you will move forward, you will ford that river to a more progressive future in which racism is condemned and Americans who look different from you or believe different things no longer live in fear—but not if it requires getting your shoes wet. Carry me, my fellow Americans! Carry me across this one more time, and I promise I'll be right there marching with you again when we've reached the next dry road.
If you cannot tell the difference between the rhetoric and policies espoused by the Republican Party during the Obama presidency and that of the Democratic Party during the same period, or between now-nominee Donald Trump and now-nominee Hillary Clinton in specific—and it seems Jill Stein is among those who cannot, or who is willing to at least pretend at it—then you are declaring that those differences are no big deal. The xenophobia, the racism, the angry nationalism, plus the declarations from a sitting House member on the accomplishments of the white race, the insistence that religious rights of employers trump those of their employees, the mocking of the very notion that the American worker might deserve a little more than mere poverty, papers please laws targeting minority drivers and voters—those are all so unimportant to you as to be mere background noise to your own complaints. That does not speak well of your political acumen. It suggests a person who is not, in fact, paying attention.
It is something that can be spouted only by people who feel that the worst abuses of the idiot man-child and his allies will not fall upon them. They are not, after all, the ones being targeted. So the risk can be taken. You can be assured that the people whose shoulders that risk is being heaped upon, however, will notice.