I tend to roll centrist but it depends on the specific issue. For example, geopolitics, I am a hawk but I am also pro-choice. Green movements fail just like any of the other fringe parties. Their scope is too narrow and their adherents too extreme. Most of the green folks are what we call 'progressives', that explanation alone should suffice. But yea, the issue with third parties in America is that their appeal is not broad enough. They mostly focus on one or two things but completely ignore other very important factors. If you check out Bernies or Jills stance on geo-politics, you will notice they won't say much because they know their kumbayah message won't fly. Just one example.