Humanism and Anti-Humanism

A problem I've been working on:

As a humanist, I believe in the brotherhood of humanity. That is, the shared identity of being human is primary, and I have no intrinsic quarrel with any other person. But the humanist must be ready to deal with the anti-humanist, generally the chauvinist (who believes in the irrational superiority of his own group).

Now, irrationality does not suggest inferiority. Cultural identity is axiomatic to the chauvinist, just as human identity is to the humanist (I've been very concerned about cultural identities lately, for this reason). But at the most extreme, the chauvinist is prepared to treat the humanist as an enemy based on what the humanist takes to be a trivial detail. What is the appropriate response?

Ethically, the humanist is obliged to be reasonable for as long as possible; these things are rarely cut and dried, and many things that can be seen as conflict are merely failures to communicate. Again, in the most extreme case, rationality no longer plays a role -- we've entered into a sort of Hobbesian state of war between human and human. This may be obvious upon consideration, but peace and rationality rely on mutual consent -- there is no such thing as a unilateral peace.

At this breakdown, there are two choices. One gives primacy to self-defense; once the state of war is entered, one may take any action necessary to defend oneself or others from harm (harm to others must be considered harm to the humanist). This gives rise to the notion that the good are obliged to be dangerous.

The other option is pacifism, which rejects the state of war even at this point. And who is to say this is incorrect? I have mentioned the power of non-violence in discovering the humanity of the oppressor (the anti-humanist is still human at all times). A purely pacifist approach may be going even further, though.

Does the pacifist err in refusing to separate the just cause from the unjust? Or does he achieve something greater, by means of a leap of faith? I don't know that it can be determined. In practicality, one rarely deals with this momentous choice. Still, I think it is informative in how one identifies and deals with opposition of all stripes.