"Everyone knows she's a Marxist," Republican presidential hopeful Donald Trump has repeated loudly and often, referring to his Democratic rival Kamala Harris, who he is hoping to tar with one of the oldest brushes in the US political playbook.
The aim? To portray Harris as a dangerous left-wing extremist, and to invoke the infamous Cold War-era "red scare" in the United States.
In recent weeks, the former president has stepped up his rhetoric against the vice president, describing her as both a "Marxist" and a "communist" at almost every opportunity.
Harris has not directly addressed the taunts, but her policies over decades of holding public office do not appear to conform to either the 19th-century German theorist's views or the various left-wing schools of thought that followed him.
"She's not a Marxist, she's not a communist," said Thomas Zeitzoff, a professor at American University and a specialist on political violence.
For the Republican camp, using such terms is "a way of trying to say that she's extreme," he told AFP.
Trump, experts say, is using an age-old US political tactic called "red baiting," which aims to discredit an opponent by accusing them of not being a capitalist.
The strategy involves labelling an opponent as a "communist," "socialist," "Marxist," or a "red," said Barbara Perry, a presidential studies professor at the University of Virginia.
It is "an attempt not only to denigrate them, but also to get them to fight back and maybe present themselves in a not very nice way," she added.
Perry said the terms were "very weighted" in the United States, and invoke the repeated "red scares" of the era following the two world wars, when Washington was competing with the Soviet Union for dominance.
"The country tends to turn inward at those times" of competition with a rival ideology, she said.
The most well-known example of the "red scare" phenomenon was practiced by US Senator Joseph McCarthy, the chief "red baiter and the witch hunter in the Senate," Perry said.
A fervent anti-communist, McCarthy warned of the supposed infiltration of communists into every stratum of American society, creating a widespread climate of paranoia across the country.
"Red baiting also has this... long history in the US, and it's kind of interesting to see it sort of come back," said Zeitzoff.
He also identified a common thread running between McCarthy and Trump: a lawyer named Roy Cohn.
Cohn was an advisor to McCarthy, and in the 1970s became a mentor to the real estate magnate and future president of the United States, Trump.
Harris only became the Democratic Party's presidential candidate in July, after President Joe Biden dramatically dropped out of the race following a disastrous debate performance against Trump.
With voters having a limited time to get to know the vice president, Trump has attempted to influence their image by repeatedly characterizing her as a communist.
To explain why Trump has done this, both Zeitzoff and Perry use the same metaphor: that of throwing spaghetti against the wall and seeing what sticks.
Trump appears to be trying to attract a certain type of voters by calling Harris a "Marxist," said Zeitzoff, particularly Hispanic and Latino Americans.
Many voters from that background may have come from families that fled communist countries and therefore have unfavorable views of them.
Trump is also targeting another demographic with this rhetoric: older voters.
"There will be some people in the electorate who are remembering, as I can... the height of the Cold War," Perry said.
"So there will be, certainly, people who know that communism is bad and think communism is bad to this day."
In his book "Nasty Politics," Zeitzoff argued that the use of insults, conspiracy theories and aggressive rhetoric was not particularly effective in influencing voters to change camps.
Nevertheless, with the current election on a knife-edge -- the candidates are neck-and-neck in most polls, including in battleground states -- Trump's red baiting could make a difference.
"The margins are really narrow. So maybe this, you know, is persuadable to some people at the edge," Zeitzoff said.
