In reviewing Kamala D. Harris’s performance in Wednesday night’s vice-presidential debate, two thoughts occurred to President Trump.

“Totally unlikable,” he said during an interview on Fox Business. He also called her “a monster” — twice.

Trump, who has never been big on reading, is probably unaware of the historical roots of his likability and monster critiques.

To historians who study women in politics, it was obvious.

“Likability among male politicians is pretty exclusive,” said Claire Bond Potter, a professor of history at the New School and the author of a book on political engagement. “This is part of a bigger problem that women have — a permanent outsider status in politics. They are always in the process of gaining entry.”

One of the ways to deny women entry is to deny anyone would want to be around them in the first place. The suffragists felt this wrath. So did Hillary Clinton. And now Harris is, too.

The code words are everywhere.

“One of the things that a man has to do to become likable is to be perceived as the kind of guy you want to have a beer with,” Potter said, referring to a phrase that was often used to describe Bill Clinton, George W. Bush and John McCain. “You know, it's very rare that one imagines getting to know a woman over a beer. And you never hear anybody say that he's the kind of guy you'd like to sit down over a glass of wine with, right?”

Trump and other male politicians know how to tap into that history of misogyny.

“These ideas are woven through society and really always have been,” said Allison K. Lange, a professor of history at Wentworth Institute of Technology and the author of “Picturing Political Power: Images in the Women’s Suffrage Movement.”

In her book, Lange examined how the ideas surrounding “political womanhood” took hold in the earliest days of the country when Martha Washington, the dutiful wife of the nation’s first president, became an icon to opponents of giving women the right to vote. This status was pushed — mostly by men, of course — long after Martha’s death.