As Yglesias puts it:
After all, there's not a dime's worth of a difference between a candidate promising tax cuts, pushing more health risk onto individuals, a re-invigoration of George Bush's campaign to dominate the world through military force, and an industry-friendly approach to environmental issues and his rival who's promising substantial socialization of medical risk, a 80 percent reduction in carbon emissions, and end to the war in Iraq (and to the mindset that led to war!), universal preschool, etc. Well, sure, there's judicial appointments -- abortion, gay rights, etc. -- and some small fry stuff about whether or not the NSA will have unrestrained surveillance powers. But basically it's just the same two corporate clones running on virtually identical platforms.Update: James Fallows puts it a little less snarkily:
That he stayed in the race in 2000 was tragedy. (See: Invasion of Iraq, 2003, and subsequent occupation.) That he came back in 2004 was unfortunate; his entry in 2008 is farce. Farce because it suggests detachment from political reality (the differences between the Republican and Democratic nominees are so faint that we can say, What the hell!) and, worse, narcissism. The fact that it won't make any difference in the outcome actually is sad.
I will always like and respect Ralph Nader and will always admire the wonderful things he has done. But I wish to God that he had not made this decision, or will reverse it soon. (And, I am sorry that saying this will make me an enemy in his eyes.) He is a better man than his recent decisions indicate.

Yeah, but there's no difference between the Democratic candidates, Republican candiadates and Ralph Nader, either.
All of them assume that the government is the answer to our problems, rather than the cause.
Tom
Idiocy. Pure, unadulterated idiocy.
Tom - is your CD skipping?
Oh no! Maybe Huckabee could run as an independent candidate to restore balance to the force.
(Ralph Nader is no longer relevant, assuming he ever was.)
This news rocked the political markets, causing* a whopping 0% change in everyone's odds :)
*Actually, the truth is just that the odds just didn't change. It is possible that the odds would've changed without this announcement, and the announcement put equal and opposite pressure on the prices.
Mainstream media constantly make this mistake - assuming causation - when reporting on financial markets.