In the fall of 1998, as an assistant history professor recently out of graduate school, I was excited to get a call from a producer of a local CBS morning news show who had noticed a panel discussion I’d organized about the impeachment of President Bill Clinton. The producer asked me on the show to put the event in historical context. I of course accepted.

It went well, and I kept being asked back on. Even as my academic career progressed, I remained in demand as a historian who could talk in an accessible way on TV and radio about current affairs. I’ve inhabited this strange space now for more than two decades, so I’ve had plenty of time to reflect on how historians contribute to the public square. Here’s what I’ve learned about what historians get wrong—and can get right—when they do so.

The main pitfalls involve clichéd shorthands or tropes—tempting to use when communicating with a lay audience, but distorting and reductive. There are five, in particular, I’ve heard too many times.

Unprecedented: We use the word because it seems a surefire way of getting attention in a media environment that is constantly searching for novelty. Fundamental breaks are more newsworthy than more of the same. For the historian, it’s also a way of stepping into the shoes of contemporary observers who feel as if something could never have happened before.

The problem is that unprecedented can be misleading: To say something is without precedent ignores comparable phenomena in the past, even if they took a different form. Consider President Donald Trump’s penchant for false statements: To declare his lies “unprecedented” risks downplaying how much presidential lying we’ve seen throughout American history. How should we weigh Lyndon B. Johnson’s 1964 fabrication about an attack by the North Vietnamese in the Gulf of Tonkin—which became the pretext for one of the United States’ most catastrophic military interventions ever—with Trump’s habitual lies? Or George W. Bush’s grossly exaggerated claims about Saddam Hussein’s weapons of mass destruction, which proved false after being used to justify a disastrous invasion of Iraq that lasted from 2003 until 2011?

Similarly, talk about today’s “unprecedented” polarization in Washington ignores most of American history. As the Yale historian Joanne Freeman has shown, legislators regularly brought pistols and other weapons to the floor of Congress in the mid-19th century, and physical fights broke out among members. More recently, in the 1990s, House Speaker Newt Gingrich abandoned old norms of bipartisan conduct by urging his Republican colleagues to attack Democrats as “anti-child,” “pathetic,” and “traitors.” Political scientists were producing mountains of work on the shrinking center, the rise of party-line voting, and the breakdown of civility back when Trump was famous mainly as a fixture on Page Six of The New York Post.