A quick note on what we mean by "ultra-leftist."

An ultra-leftist is someone who clamors for things for which the material conditions don't exist yet. For example, with regards to the Syrian conflict, most MLs support the Syrian government against the "rebels" *even though* the Syrian government is a bourgeois nationalist government. Why? Because in a fight between the national bourgeoisie of a country and the imperialist bourgeoisie, the national bourgeoisie represents the progressive force. This of course does not hold if the conflict is between say the national bourgeoisie and the working class, in which case the workers would represent the progressive force and we'd switch our allegiance.

This is a basic application of dialectical materialism: the fact that what is reactionary in a particular situation can be a progressive force in another situation. Things aren't static and rigid but are continually changing. Capitalism was a progressive force against feudalism but is reactionary against socialism. The French Revolution was a progressive advance against feudalism even though it was a bourgeois revolution. This is the Marxist position.

The ultra-leftist position is: no, full communism in Syria! This ignores the existing material conditions in Syria, misunderstands the strength and position of the proletariat, and jumps to establish the ideal society by ignoring the messy present. This, of course, results from a gross misunderstanding or lack of knowledge of dialectics which make them hold to the position that nationalism or the bourgeoisie are always and always "bad."

This is what an "ultra-leftist" is. It's not someone who's the farthest left on the political spectrum (please) and it's not something to be proud of (at least if they understand the way Marxists use the term against them).