Let's forget Saul Alinsky, shall we? This looks a lot more interesting! From page vii of Practical Agitation by John Jay Chapman:
The idea is, that we can always do more for mankind by following the good in a straight line than we can by making concessions to evil. The illusion that it is wise or necessary to suppress our instinctive love of truth comes from an imperfect understanding of what that instinctive love of truth represents, and of what damage happens both to ourselves and to others when we suppress it. The more closely we look at the facts, the more serious does this damage appear. And on the other hand, the more closely we look at the facts, the more trifling, inconsequent, and absurd do all those reasons appear which strive to make us accept, and thereby sanctify and preserve, some portion of the conceded evil in the world.
Contrast Saul Alinsky, who sounds like he sat at the feet of Leo Strauss:
"An organizer working in and for an open society is in an ideological dilemma to begin with, he does not have a fixed truth -- truth to him is relative and changing; everything to him is relative and changing.... To the extent that he is free from the shackles of dogma, he can respond to the realities of the widely different situations...." pp.10-11
Now, it's probably unfair to compare Chapman to Alinksky, since Chapman appears more of an essayist/historian than an organizer. Nevertheless, starting the book, he's got what reads like a useful (and hopeful) take on how the Boss Tweed organization was brought down -- surely a level of corruption comparable to our own.
NOTE Hat tip, Hugh and VastLeft in comments.