In 1990 gopac, a Republican training organisation, sent a notorious memo to conservative candidates. It contained a list of positive words they should use in relation to their own party, such as “courage”, “truth” and “vision”, and negative ones to attach to Democrats, like “corruption”, “greed” and “stagnation”.

The memo’s legacy has not turned out how its authors intended. Today, Democratic lawmakers use words on its list more than Republican ones do. To evaluate the partisan slant of American media organisations (see main story), we needed to produce a list of terms that reliably distinguish the two parties’ language.

To develop our phrasebook, we gathered all speeches made in Congress between 2009 and 2022. We split the text into two-word phrases; removed uninformative words such as “in” or “the”; and de-stemmed the remaining words, so that, for example, “addiction” and “addicted” both become “addict”. This left us with a mere 2m word pairs. Next, we narrowed this list to phrases used almost exclusively by one party, and chose the phrases used by the greatest share of that party’s legislators.

The resulting list of 428 terms fell into two broad categories. One is duelling labels for similar topics. People who enter America without permission are “undocumented immigrants” to Democrats but “illegal aliens” to Republicans. Democrats refer to firearms as a “gun epidemic”; Republicans as the product of their right to “keep and bear arms”. Abortion, to Democrats, is “reproductive care” to which women once had a “constitutional right”. Republicans, meanwhile, bemoan the “abortion industry” violating the “sanctity of life” of “unborn babies”.

When discussing policing, Democrats tend to bring up George Floyd or Breonna Taylor, unarmed black people who were killed by police, whereas Republicans invoke the “thin blue line”—the notion that only police can save society from chaos. On electoral integrity, Republicans fears about “ballot harvesting” are matched by Democratic ones over “dark money”.

The list contains many phrases about subjects that one party is eager to discuss, and the other prefers to avoid. Republicans love to rail against “burdensome regulation”, “government overreach” and “unelected and unaccountable officials”, as well as taxes, particularly the “death” and “job-killing” kinds. They also regularly discuss “almighty God” and the rights he has given you. Democrats, in contrast, play up environmental woes like the “climate threat”, “rising sea levels” and “big oil”, and the plight of downtrodden “communities” that are “marginalised” or “of colour”. They also show a penchant for discussing “doughnut holes”—not the edible sort, but the kind found in Medicare prescription-drug coverage.