The Green Party, and people who use the more generic label of "green," rightly chastise climate change deniers for not "following the science."
But, you can't make that claim, and then have official support for "alt-med" (often, it's really pseudo-med) in your official 2004 and 2008 party platform, without leaving yourself open to charges of hypocrisy, even rank hypocrisy. (I have emailed state-level Green representatives, months ago; we'll see if anything changes this year.)
That's somewhat the same on issues of modern agriculture. Setting aside the fact that organic agriculture, even non-corporatized organic, uses pesticides and herbicides in many cases, and that many of these are actually more toxic than commercial varieties, then, there's the blanket opposition to genetic engineering.
Mike at Science Blogs does a generally good job of getting at this issue. I think he could have addressed greens' concerns a bit more, but he's generally on the right track. Not every GMO change creates a "Frankenfood," not every GMO or other change is under the control of a Monsanto, though a number are, and, an ongoing (note that stress, because we've done that for decades) scientific approach to agriculture is still the best bet for future world food needs, closely seconded by better political stability in many places for food distribution. (Organics, per acre, generally have a lower yield, meaning that it's going to take more land to feed them to more people.)
So, why do I vote Green?
I do believe in many of the party's official positions. Plus, the Democrats, especially nationally, but also here in Texas, largely continue to drift, if not actively move, further right. And, there's the combination of protest vote and punishment vote.
So, I'll continue to vote Green, and continue to tout Greens vs. Democrats. I won't necessarily avidly tout Greens by their own lights, though.
But, what's really needed is per a blog I started several years ago: a "Science and Reason Party." Behavioral economics shows how wrong and unscientific modern conservative American economic theories are; modern social sciences show how unscientific most religious right shibboleths are; modern hard science shows how wrong the anti-science not only of the far right but the "woo" people of the left is.