The problem with many self-styled radicals is that they are seemingly unable or unwilling to accept the basic fact that ANY election (not just those in the US) is a multiple choice rather than essay exam. If you want to be counted, you need to pick from among the choices listed by the test authority figure instead of scribbling your own alternative answers. Every C or above student understands the difference between the two.
More seriously, if one wants a better, more progressive politics, the place to start is to change the power balance on the ground, organize people and set up institutions who can effectively counterbalance the power of business, produce a class of public figures who will publicly espouse that agenda, set up the propaganda machine that will effectively popularize that agenda, and only then run candidates to political office on that agenda and expect them to win. Getting serious about DNC politics is a good place to start.
Thos who come to the game just before the election and ask people to "vote their conscience" and similar rubbish are like that guy in an old Polack joke who brings a duck to a cockfight.
Wojtek