There are people in the world who get killed trying to get the right to vote. There are people who get killed trying to exercise the "right" to vote that they already have.
What's wrong in this country right now is that far too many of us are too lazy or ignorant to keep up with what's going on in politics, and then vote when it comes time to do that; what's wrong is not that too many of us are voting now, it's that too many of us aren't. When you think about what so many people in the world need to go through to make themselves heard, we really don't have any right to sit out elections just because we're pissed off that Democrats aren't doing enough.
Look at 2006 in Connecticut: Do you think that Lieberman won there because too few people sat out because Lamont wasn't liberal enough? Lieberman won because too many people either didn't bother to find out what the diffreences were between the guys or because they knew but couldn't be bothered to show up and pull the lever on election day.
We don't have it so hard when it comes to voting here in this country: we have to go out and stand in line a little while twice each election year. (In Virginia, where I live, we have a primary and a general election every year, unlike in some states, where it happens only in even years.) We don't have to get by a line of thugs trying to beat us up for voting; we don't run the risk of getting shot for speaking our minds. We're lucky here.
If you aren't happy with the way things are going--and I'm not, either, and I'm guessing few people here are--then do something about it: go out and volunteer. Go canvassing door to door, as I did earlier this year. Sit in a seedy office and make calls, as I did last year. Sit out on your ass for 13 hours as a poll watcher, the way I did in 2006, when Jim Webb upended George Allen's career. I'm proud of that.
None of that was fun; sure there were things I'd rather have been doing, though in all truth, the poll-watching was kind of fun; the weather was good for November, and I had a long and interesting and polite debate with some people who were there trying to get people to vote for a constitutional amendment to ban gay marriage (sorry to say it passed). But it was worth it, even this year, when we lost the governor's race.
So, if you don't like what's happening, then get off your ass and make something else happen. Go work for people you want to see win. If there's nobody running you like, then run yourself. You don't have to start by running for the U.S. Senate: you can run for the state legislature or the county or town council or the school board. How do you think the nuts in the Republican Party got so many seats in the 80's and 90's? It was by all those wackos winning small-time local seats and then working their way up the ladder. We can get more liberals into the system by starting small, too, but people have to be willing to do it, if not running themselves, then at least working on campaigns.
So if you don't like things as they are now, then get out and change things. If, though, you'd rather have another 4 or 8 years like the last 8 years, then sit it out next year and forever more.