Joel Kotkin writes for the Orange County Register about a disturbing trend in recent political debates.

The ongoing trial involving journalist Mark Steyn – accused of defaming climate change theorist Michael Mann – reflects an increasingly dangerous tendency among our intellectual classes to embrace homogeneity of viewpoint. Steyn, whose column has appeared for years on these pages, may be alternatingly entertaining or over-the-top obnoxious, but the slander lawsuit against him marks a milestone in what has become a dangerously authoritarian worldview being adopted in academia, the media and large sections of the government bureaucracy.

Let’s call it “the debate is over” syndrome, referring to a term used most often in relationship with climate change but also by President Barack Obama last week in reference to what remains his contentious, and theoretically reformable, health care plan. Ironically, this shift to certainty now comes increasingly from what passes for the Left in America.

These are the same people who historically have identified themselves with open-mindedness and the defense of free speech, while conservatives, with some justification, were associated more often with such traits as criminalizing unpopular views – as seen in the 1950s McCarthy era – and embracing canonical bans on all sorts of personal behavior, a tendency still more evident than necessary among some socially minded conservatives.

But when it comes to authoritarian expression of “true” beliefs, it’s the progressive Left that increasingly seeks to impose orthodoxy. In this rising intellectual order, those who dissent on everything from climate change, the causes of poverty and the definition of marriage, to opposition to abortion are increasingly marginalized and, in some cases, as in the Steyn trial, legally attacked.