I disagree with his claim. What separates someone like Rothbard from Proudhon is primarily their theories of value, the product of which being an acceptance of wage labor for Rothbard and a rejection of it from Proudhon. The men otherwise were remarkably similar in their critiques of the state, provided one accounts for Proudhon's distinction between property and possession. Proudhon, especially later in his life, developed a remarkably contractarian and voluntarist orientation. He became somewhat disillusioned with the rising socialist labor movement and began championing federalism (political decentralization) more than any other issue during his tenure in parliament. This small distance between the two anarchist traditions is even more shortened when one looks to the American anarcho-individualists. Lysander Spooner shared Proudhon's modified labor theory of value more or less, but he was also a natural rights philosopher and both an abolitionist and against the Civil War like Rothbard would later be (calling his position Copperhead Abolitionism, after the anti-war Copperheads of the Democratic Party). Benjamin Tucker even called his creed "unterrified Jeffersonianism" and "consistent Manchesterism."
