he academy’s raison d’être is to be a place where scholars fearlessly examine ideas, however controversial, in order to reject falsehood and pursue truth. In recent months, however, student protesters and faculty agitators have forced the disinvitation of such commencement speakers as Condoleezza Rice and Christine Lagarde, caused a Yale lecturer to stop teaching after she suggested the school should not police students’ Halloween costumes, and heckled speakers such as the American Enterprise Institute’s Christina Hoff Sommers.

More troubling were the student and faculty protests last fall at the University of Missouri, which forced both the president and the chancellor to resign when they were accused of responding complacently to instances of racial bias on campus. (Whether some of these incidents even occurred remains a contested question.) After student journalist Tim Tai was forcibly ejected from one campus protest, assistant professor of mass media Melissa Click, who has since been fired, called on activists to similarly “muscle” student Mark Schierbecker from the scene. The protesters explained that they feared the journalists would advance the media’s “twisted, insincere narratives.”

Speech suppression is not confined to campus. Protests caused the Mozilla software corporation to fire co-founder and former CEO Brendan Eich after it came to light that in 2008 he had donated to groups supporting California’s Proposition 8, which banned gay marriage. The conservative Heritage Foundation sacked Jason Richwine after activists “discovered” his Harvard Ph.D. dissertation exploring the possibility of natural IQ differences between races—a dissertation approved by a committee of liberal professors. The case of Justine Sacco shows just how swift and brutal the social justice mob can be: the formerly unknown public relations executive wrote an insensitive tweet about AIDS before boarding a plane from California to South Africa, igniting a firestorm on Twitter. Thousands of armchair activists excoriated Sacco using the hashtag #HasJustineLandedYet, and at least one participant in her public shaming showed up to meet her at the airport. She had been fired from her job by the time she landed.

Against the backdrop of these frenzies, Townhall Columnists and Fox News contributors Mary Katherine Ham and Guy Benson offer End of Discussion: How the Left’s Outrage Industry Shuts Down Debate, Manipulates Voters, and Makes America Less Free (and Fun). Ham and Benson chronicle the range of issues on which the Left condemns their ideological opponents as racist, sexist, or simply evil: “association with the ‘wrong’ fried chicken joints, Internet browsers, breast cancer charities, pasta, children’s toys, Halloween costumes, TV shows, schools, and even comedians’ jokes.” They ably tell the tales of those like Eich and Sacco, and expose the cynical gambits of the powerful to quash dissent. Democratic Senator Chuck Schumer, for example, advises his fellow elected officials to characterize Republican ideas as “extreme.” Being beyond the pale of public consideration, there is no need to inquire whether GOP proposals are marred by errors of fact or logic.

The authors also outline the political and social stakes for dissenters from liberal orthodoxy: the shooting of a security guard at the conservative advocacy group Family Research Council after the Southern Poverty Law Center labeled the organization a “hate group”; or the 2009 Department of Homeland Security report that warned of an increase in right-wing extremism in response to President Obama’s election. (The report’s definition of “extremist” included those who “reject federal authority in favor of state and local authority,” i.e. most principled conservatives.)

While End of Discussion usefully highlights the Left’s excessive capacity for outrage, the authors do not fully comprehend the implications of left-wing speech suppression. The book both benefits and suffers from the fact that it is humorously written, and intended for a popular audience. Ham and Benson refer throughout to the Left’s “outrage circus.” But circuses are more amusing than threatening. Laughing at the Left risks minimizing the significance of their understanding of justice, an understanding that opposes and is meant to supplant America’s traditional notions of right and wrong.

The attitude of the intellectual Left towards speech and its relationship with justice is captured in Herbert Marcuse’s 1965 essay “Repressive Tolerance.” Marcuse—the favorite theoretician of radical students in the ‘60s—proposed that society should practice “discriminating tolerance” in lieu of mere tolerance. Intellectual elites must teach radical minority groups to be “militantly intolerant and disobedient to the rules of behavior which tolerate destruction and suppression,” while stamping out those “policies, conditions, and modes of behavior” that “imped[e], if not destroy, the chances of creating an existence without fear and misery.” For Marcuse, justice demands intolerance towards certain ideas, particularly those of political conservatives and others invested in upholding the status quo.

Unsurprisingly, many of the most egregious violations of free speech occur in the academy— the students who learned from Marcuse are today’s tenured faculty. Professors and their prized students have long provided the progressive vanguard. That the openly socialist Bernie Sanders has been so warmly embraced by the Democratic electorate is testament to the work of the intellectual elite in mainstreaming once exotic ideas.

Against the decades-long effort by the radical Left to fundamentally transform America, Ham and Benson admonish their readers to “chill the hell out,” to refuse to participate in the latest outrage, to stop singling others out for public opprobrium, to voice opinions fearlessly, and to, “Ask yourself, ‘Might I fit the lefty stereotype of a close-minded conservative?’” If you enjoy media wherein you “almost exclusively consume viewpoints with which you’re heavily disposed to agree,” and if you can’t remember the last issue on which you’ve “genuinely listened to a left-of-center friend, and perhaps changed your mind,” you’re part of the problem.

This advice might work with the remaining liberals of good faith who stand against the authoritarian silencing of dissent. But it won’t work with the intellectual Left. Earlier this year, a columnist for Duke University’s student newspaper wrote that since government can’t be trusted to adequately “censure hate speech,” those working to “build a genuinely free society” must do so by shouting down any speech that offends them. The columnist provides the notably liberal Duke administration as an example of institutional racism, so one can only imagine the shouting he plans for card-carrying conservatives. That some conservatives haven’t recently been swayed by liberal friends is beside the point. Cooling it won’t work. The intellectual Left is engaged in a concerted campaign against free thought. We can’t make them go away by simply rolling our eyes.