From the New York socialist movement's birth, sectarianism and dissension ate away at its core. Substantial numbers of SP members expressed deep and abiding dissatisfaction with the brand of reform socialism advocated by the party's leadership. To these left-wingers, constructive socialism seemed to stress insignificant reforms at the expense of ultimate goals. How, these revolutionaries angrily demanded, could the SP hope to attract workers if it did not distinguish itself from the many progressive parties, if it did not proffer an enduring and radiant ideal? How, the constructivists angrily replied, could the SP hope to attract workers if it did not promise them immediate benefits, if it did not concern itself with their present burdens?...(via Brad DeLong)
Through its own internal feuding, then, the SP exhausted itself. forever.... The story is a sad but also a chastening one for those who, more than half a century after socialism's decline, still wish to change America. Radicals have often succumbed to the devastating bane of sectarianism; it is easier, after all, to fight one's fellows than it is to battle an entrenched and powerful foe. Yet if the history of Local New York shows anything, it is that American radicals cannot afford to become their own worst enemies. In unity lies their only hope.
— Elena Kagan, 1981 undergraduate thesis, Princeton University
[Note: Princeton University has blocked the internet distribution of Kagan's thesis. The thesis is available from Princeton University for $54.60.]