First, yes, the Nader we see today is pretty much the same guy from 20 or 30 years ago. The difference is this: the same qualities that made his work successful in the past - stubborness, intractability, willingness to attack the two major parties, audacity, not to mention the ego necessary for all of the above - are being wasted on a vanity run, a goal many of us seem to agree is ... for shit. (And, is it just me, or is this run reminiscent of Ron Burgandy's description of himself in "Anchorman"; "Um, I'm a pretty big deal." Grab me a scotch, Ralph.)
I am not a Naderite and not even really an ex-Naderite. The only reason I've defended him is because I agree with one basic point: the two-party system is broken and needs to be fixed.
The reason Nader pisses me off now is that he's absolutely wrong raising the need for a multi-party/diverse political voice in this context; it's a stupid tack, especially in light of the 2000 election and the obvious division that it brings out in the left/liberal/progressive/whatever. The only fix I see is a combination of campaign finance reform and finding a system (Instant Runoff, parlimentary elections, or some other systemic election reform) whereby a viable third party candidate can run a real campaign without causing the bullshit that we've seen in the past, "siphoning votes", etc... Neither finance reform nor election reform will happen through a presidential campaign. They might happen, but it'll be a tremendously slow process because the two major parties don't want them (particularly election reform). IF they ever do happen it will be by bringing outside/third-party candidates into Congress and statehouses in large enough numbers that reform can actually happen. In some States there are ongoing efforts to make some of these changes. So, IF Nader should ever run for anything, (IF... I said, IF, damn it!), he should run for a Senate or House seat and many others from the 'progressive' side should be doing the same right now.
With Congressional Democrats currently as low in the polls as Bush, this would actually be a prime time to get more progressive Democrats, independents, Greens, whatever, into Congress.
He's not only fucking with '08 elections, he's also fucking up an opportunity.