Personally, I've never backed a winning presidential candidate. I've campaigned for Ralph Nader, Mike Gravel, and now Bernie Sanders, the left-flank challengers in each of their respective elections. The closest I've come to winning was when I voted against three right-wing candidates - Clinton, McCain, and Romney - but wanting them to lose is of course a quite different thing from wanting Obama to win. I don't know the satisfaction of seeing my ambitions and aspirations realized in a national election, and it's entirely possible that I never will.
As I've written before, defeat in an election can be pretty traumatic - elections are one of the few formal opportunities we have left in late capitalism to exercise any kind of political agency, so we invest a disproportionate amount of our hopes and anxieties in them.
But in my experience, it doesn't have to be that way. And in fact, it's generally a good idea for leftists to disinvest themselves from elections, and to recognize the extraordinarily limited role they should play in our activism. Even poor old Noam Chomsky, who gets IRL mad at the liberal media and is famously not actually laughing about any of this, has taught himself to disengage:
I think [voters] should spend five or ten minutes on it, seeing if there's a point in taking part in the carefully orchestrated electoral extravaganzas...It's just a matter of deciding, "Should I spend this little amount of time doing something which is not insignificant, but which is not of great importance either." The main point is to keep try to keep working to change the society...The electoral season in the United States, the quadrennial extravaganza, typically tends to draw energy away from activism because people are caught up in the hoopla and the excitement and so on.The more you appreciate the limitations of elections, and of the presidency in particular, as a vehicle for progress; the more you invest yourself in the substantially broader, ongoing project of left activism; and the more you come to appreciate the way the spectacle and seduction of the former undermines the latter - the more all of this comes into play, the less significant it feels when your left-flank candidate loses once again.
Liberals generally don't get this, for two related reasons. First, because they are used to winning. Despite their occasional self-aggrandizing posture as fighters, liberals generally tend to get what they want out of politics. Democrats quite often win, and even when they lose the loss is often just the setup for an emotionally satisfying dramatic arc of taking power back over two to eight years. Second, because the system is working for them, liberals become extraordinarily invested in it. They consume politics as a form of entertainment and develop creepy parasocial relationships with political celebrities. The vicissitudes of partisan fortune become, for the liberal, so caught up in psychodynamics of personal agency and codependency that electoral defeat can trigger a serious emotional and spiritual crisis.
For this reason, liberals often have a hard time understanding the impersonal and even cynical view leftists take towards politics. They personally identify with their preferred candidate, and suspect that opposition amounts to some kind of personal hatred; they assume that leftists relate to politics in the same way, and that an electoral defeat, for them, would bring with it the same quality of disappointment. Sometimes, they're right about this - but as the leftist emancipates herself from this ideological cathexis, and takes the long view of elections from the broader perspective of class struggle, these things matter a lot less.
In the next few days, Bernie Sanders is likely to end his campaign and endorse Hillary Clinton for President. This was always the most likely outcome of this election, and it is by any measure an extraordinary and unprecedented historical achievement that Sanders did as well as he did. Ralph Nader won 2.75% of the vote in 2000. Mike Gravel finished with less than one percent in 2008. Sanders, having run well to the left of both, is likely to finish his campaign with around 43% of the popular vote. I have never been so optimistic.