<additional grouchiness cut>
Maybe there is a synthesis between the two positions. Incremental reforms are huge drains of energy, and don't lead to the big reforms - just as one side says. We have a tiny chance of winnning some of the incremental reforms right now, and (in the short run) none of winning the big ones. So why not rely on an oldtime standard left tactic. Support the incremental reforms but use them as educational tools for the major ones. In other words support fair share for Walmart, but while campaigning for it, point out all the things it doesn't accomplish that Single Payer would. Campaign to get 5,000 people added to basic health in Washington State (which all the single payer groups supported) while pointing out how many it leaves uncoverred, how much is being wasted by our current system. In short, agitate for what you might get, educate for what you want, and see if you can't build a movement that can fight for the big steps.
This still leaves the question of use of scare resources, and there I stand with Doug. Take a bit from the incremntal reform campaigns, and the money donated to Democrats - not all but some. Put it into educating people about some of the fundamentals. Of course this is making an assumption that the union leadership actually favors the big steps, which is one hell of a big assumption. If you ever want to get to the big steps, then you can't put everything into the fight for crumbs - even though those crumbs are life and death for many people.