Here’s a term you need to know — the “Overton Window.” Developed by the late Joseph Overton, a former vice president of the Mackinac Center for Public Policy, the “window” refers to the range of acceptable political discourse on any given topic. As the Mackinac Center explains, “the ‘window’ of politically acceptable options is primarily defined not by what politicians prefer, but rather by what they believe they can support and still win re-election.” The key to shifting policy lies not so much in changing politicians but in changing the terms of the debate. In other words, “The window shifts to include different policy options not when ideas change among politicians, but when ideas change in the society that elects them.”

The Left — dominating the media, the academy, and pop culture — is unmatched at moving the Overton Window. Consider gay marriage, a subject once so far outside the mainstream that less than 20 years ago, Republicans and Democrats united to pass the Defense of Marriage Act to define marriage under federal law as the union of one man and one woman. Now? That view is such an anathema that it’s difficult to get — or retain — a job in entire sectors of the economy if you openly hold to the traditionalist position on marriage.

The Overton Window moved even faster on transgender rights. Ten years ago the notion that a man with emotional problems and breast implants could be named “Woman of the Year” was unthinkable. Now, in some quarters it’s just as unthinkable to refer to Bruce Jenner — Bruce Jenner! — as a man.