In today's Wall Street Journal,, Peggy Noonan asks a question that I have been wondering about as well. She attempts to come up with an answer, suggesting that "what is missing on the American left is an element of grace--of civic grace, democratic grace, the kind that assumes disagreements are part of the fabric, but we can make the fabric hold together."
I agree with that, but there are two more profound reasons for the penchant on the Left to stifle dissent. One is an observation that Dennis Prager is fond of making: that conservatives view liberals as being foolish, naive and wrong; while liberals view conservatives as being evil and worthy of being hated. One sees this tendency most clearly in the nearly hysterical criticisms of President George W. Bush, sometimes comparing him to Hitler and attributing to him only the worst of motives. If one's political foe is a servant of evil, if not the Father of Evil himself, it seems only right to deny him the right of free speech. On the other hand, if one views his political adversary merely wrong-minded, as conservatives tend to view liberals, then free and open debate may serve to expose the errors of his thinking, and perhaps even persuade him of the correctness of the conservative position.
The second, and uglier, basis for this stifling of dissent comes from the idealogical roots of today's political left, in the New Left of the 1960s. I was strongly exposed to the New Left, and even participated in its activities, at Stanford from 1969 through 1972. The New Left was strongly influenced by Marxism-Leninism, especially of the Maoist variety. It adherents believed that traditional political liberalism--the ideals represented by the Bill of Rights--represented bourgeois morality. Such mores were not to be taken seriously. If tactically useful, the Marxist-Leninist could use such values as political weapons to aim at the ruling class, by accusing political opponents of McCarthyism and fascism. However, the Marxist-Leninist did not really believe in political freedom or free speech or civil grace as objective ideals, which should be enjoyed by one's political adversaries as well as by the Left. Hence, the very leftists who demanded academic freedom for Marxist-Leninist scholars would not hesitate to disrupt speeches or classes given by anti-Marxists, or to use their positions as professors or teaching assistants to threaten students with politically incorrect views with failing grades. As David Horowitz , himself a former New Lefty, has documented, this stifling of dissent continues on campus today, and perhaps is even more firmly entrenched, because the students of the 1960s New Left are the tenured college professors of today.
Of course, the far right is not immune from these tendencies to stifle the speech of political opponents, and my fellow Zionists often are to quick to try to suppress the views of those critical of Israel, but for pure, unadulterated, ideologically motivated opposition to free expression in our time, look to the Left.