Please forgive if this comes off as stilted/awkward- typing it out from an iPhone. Wanted to get in on he action before this conversation disappeared. Specifically wanted to address point b) ("why should I feel a duty to fix that which I'm abandoning?")
Just because you can't immediately identify anything America has done for you lately doesn't mean that you haven't actually benefitted from living here. Trade agreements? Food and drug regulations? Educational grants? And then there's national security. Ugly, underhanded, over-reaching... Effective. Like it or hate it, the US Iis still, for the moment, one of the world's primary powers. Which brings all kind of heat on us, not only as a nation but also, potentially, as individuals. You benefit from living here. The state provides some definite services for you as a citizen. It also does some nasty shit in your name.
So why should that count as an argument in favor of "buying into the system?" Well, way I see it, it's less about condoning a reprehensible political structure, and more about taking some amount of ownership of that structure. Yeah, we benefit from living here. And that benefit, your comforts, we're built and are sustained on the backs of he less fortunate. Abstaining from the vote, in my opinion, isn't just kind of a passive-aggressive gesture (although I agree with humanodon- it's that too), it's incredibly hypocritical. To say something along the lines of "I'll continue to live here and accept all the wealth and security that American life affords, no matter the cost to other world actors... But I won't vote for the guys who help make the decisions that help secure my wealth and safety..." I mean, that's a denial of culpability, isn't it? That's accepting the service without paying the tax.
Almost didn't vote last national election, because I was feeling the way you do (presumably). Two things changed my mind. First was the above thought process, more or less. Second was the following: yes, national politics are nasty. Yes, it's hard to see tie direct benefit from the guy on top to you personally. Yes, national office is defined more by its strictures and limitations than it is by powers for change. But. National office exists, as do the shitty choices that have to be made every day by those who inhabit those offices. That being he case, I'd better do everything in my power to make sure the most qualified guy is in office making those decisions. Even if they're shitty decisions. No, especially if they're shitty decisions. Because the alternative is allowing just any schmuck in office and make those decisions for you. As you sit back and talk about how you want no part of "the system" while at the same time reaping the benefits of that system every day. So: a) tough decisions have to be made on a national level whether you like it or not. Better make sure the people making those decisions are qualified. And when they make decisions that can generously be described as the lesser of two evils, better make sure you've accepted responsibility right along with them, rather than buried your head in that soft, expensive American sand.
That was my thinking, anyhow. And don't read all those "yous" as me pointing the finger at you personally. More just inner dialog stuff.