Anarchism is the belief that rulership is unnecessary and should be abolished. The word 'anarchy' does not imply chaos, but rather a stateless society with voluntary social harmony.
Anarchists want smaller government, and ideally no government. Henry David Thoreau put it best when he said:
"I heartily accept the motto, 'That government is best which governs least'; and I should like to see it acted up to more rapidly and systematically. Carried out, it finally amounts to this, which also I believe--'That government is best which governs not at all'; and when men are prepared for it, that will be the kind of government which the will have."Anarchists oppose theft, and thus anarchists oppose taxation. Anarchists oppose kidnapping, thus anarchists oppose the jailing of people for "victimless crimes", such as drug use, prostitution, gun-ownership, or flag-burning. Anarchists oppose murder, and thus anarchists oppose war (insofar as innocent people, a.k.a. civilians, are killed).