Spoiling your ballot is a pretty meaningless protest---if you vote for no one then you don't get no one, you get whoever (the majority of) everyone else voted for; i.e., you'd be effectively joining the 1/3 who can't be troubled to vote.

The Democrats have to give an option that isn't just a slightly friendlier corporatism

that's what primaries are for, after that, need to hold your nose

Not voting is not resistance, it's surrender, and in the US, voting for anyone other than Doofus or Baelcriggh the Unyielding is unfortunately the same as not voting. The primaries are the time to be picky.

I also am disgusted with the Democrats. But I vote in every election always, and I pay attention to all the local races. I always vote in the primaries. I have had to switch back and forth between parties to do that. That's one of the problems right there. That Bernie Sanders even has to run as a Democrat, or Ron Paul has to run as a republican is an illustration of what's wrong with our system. It would be hugely changed if we got ranked choice voting on a national level. I have voted for maybe 8 republicans since 1992, and none of them were presidential or senate candidates. There have been some pretty good good repug candidates in primaries. John Kasich comes to mind. But, Hillary was perfectly accurate when she called the Trump coalition a basket of deplorables. We're at a stage now where rampant Nazi-ism in the Repug party isn't even newsworthy. Everyone knows it.