Jay Cost urges National Review Online readers to push for a greater grasp of American political history.

Politicians of both parties engage in such stark rhetoric all the time. They know their audiences will be persuaded by it because, sadly, most voters do not know any better. It’s a consequence of public ignorance of our nation’s history, which is not good for republican government.

Historical ignorance makes for a very short collective memory. Think of it this way. Roughly 80 percent of today’s adult population is 64 or younger. This means that the age of adulthood for most Americans came sometime after 1971. Without a basic grounding in history, that date gets later and later every year, as the people at large simply — by virtue of each generation dying off — forget what has happened. At this point, memories of Reagan are fading, memories of Nixon have grown very dim, and memories of Eisenhower are soon to be gone for good.

This has substantial, albeit subtle implications for the body politic. To start, it is easy to wrongly think that things are a lot different now than they were then. Return to those above quotes from Bannon and Perez, both of which suggest some unprecedented degeneration in our politics. In their view, Trump is either a victim or perpetrator of the problem, depending on one’s partisan view. This obscures a truth that is easily overlooked if one has no knowledge of history: Politics has often been very messy. This country more or less invented mass-based politics in the early 19th century, and it has often led to hyperbole, coarseness, nasty partisanship, unfit characters in office, and all the sorts of things that people want to think are unprecedented.