… is from page 500 of the 1988 collection of Lord Acton’s writings and notes to himself (edited by the late J. Rufus Fears), Essays in Religion, Politics, and Morality; specifically, it’s a note drawn from Acton’s extensive papers at Cambridge University:
Liberty has not only enemies which it conquers, but perfidious friends, who rob the fruits of its victories: Absolute democracy, socialism.
