Kamala Harris is on track to be the sweariest president in US history

The Asian Pacific American Institute for Congressional Studies Legislative Summit seems an unlikely forum for the woman who wants to be the next leader of the free world to drop an f-bomb. But that's exactly what happened when Kamala Harris, the US vice president, addressed a gathering of young Asian American and Pacific Islander people in May. "We have to know that sometimes people will open the door for you and leave it open," Harris said, a few weeks before Joe Biden announced he would not be seeking re-election. "Sometimes they won't, and then you need to kick that f-ing door down."

A few decades ago her audience might have gasped or silently taken in the expletive, but now they clapped and laughed. "Excuse my language," Harris added. Yet it wasn't the first – and it won't be the last – time the Democratic presidential candidate publicly uttered a four-letter word.

"It was a masterclass in how to swear," says Melissa Mohr, the author of Holy Sh*t: A Brief History of Swearing . "It was boring until she said, 'kick that f-ing door down', and then she started laughing – and everybody else laughed. She grabbed their attention – it was a great example of what swearing can do."

Donald Trump, her presidential rival, also seems partial to profanity. Whether it's referring to African nations as "s-hole countries" , or calling former Republican presidential candidate Mitt Romney a "pompous ass" , Trump is renowned for deploying foul language to the extent that the politically incorrect former president is widely perceived to have made the US political climate coarser. Trump often calls his assorted indictments "bulls-", even inspiring an evangelical crowd at a rally at a megachurch in Phoenix, Arizona, recently to chant "bulls-" in support of him.

Trump may have more greatest hits, but Kamala Harris could yet become America's most expletive-friendly leader ever should she triumph in November's presidential election. The evidence is mounting that she is becoming the political doyenne of the dirty word.

During Harris's doomed 2020 presidential bid, when she was asked for her favourite curse word , she responded it "starts with an 'm' and ends with an 'uh'" (many also noted that during the recent presidential debate, she called Trump "this mo... former president".)

Harris has form with the super-expletive, having previously defended Left-wing Democrat congresswoman Rashida Tlaib for saying of Trump that she wanted to "impeach the m-r". Harris told daytime US television show The View in 2019 that Tlaib is "not the first nor will she be the last elected person to curse in public".

Asked by the podcast Pod Save America about the then president in 2017, Harris said, "I was told one should not say m-r in these kinds of interviews".

In an interview with Rolling Stone in June , referring to arguments in the Supreme Court over emergency abortions following the Court overturning Roe v Wade in 2022, Harris said: "It's f-d up." In the same interview she acknowledged her escalating expletive count: "What have I done differently since I've been in this office? I curse more." Harris has also sworn about more lighthearted subjects, telling her niece Meena Harris: "You need to learn how to f-ing cook!"

The question is, why? Is she looking to gain some campaign advantage? Or is she just a fouled-mouthed sign of the political times?

Research by software platform Quorum found US congressional politicians deployed the f-word 205 times last year on X (formerly Twitter), including retweets, compared with zero times in 2015. Interestingly, despite the linguistic belligerence of high-profile Republicans such as Trump and outspoken Georgia representative Majorie Taylor Greene, Quorum found Democrats in 2023 used the words "s-" 161 times, compared with Republicans using it 70 times; Democrats used "hell" 620 times, compared with the word being tweeted 472 times by GOP lawmakers.

"In politics it seems like some sort of dam has broken," Mohr says about the rise in swearing. "It's partly due to social media, and also American politics is very apocalyptic now with the divide between the Left and the Right. Both Republicans and Democrats see the world burning for different reasons and they feel swearing is the appropriate language to use when you're faced with existential threats. The time for parliamentary language has passed so that brings out the f-s and the s-s!"

It's a far cry from when swearing was considered scandalous in American politics and presidents wanted to be publicly sworn in, not swear in public. Richard Nixon, Harry Truman and Lyndon Johnson all frequently cursed, but only behind closed doors. When politicians did cuss, they expressed regret for being found out (such as in 1988, when George HW Bush, who would duly become president, was overheard saying he tried to "kick a little ass" after a vice-presidential debate).

Or take that staple Trump expletive: "bulls-". As late as 2012, Barack Obama caused controversy by telling Rolling Stone that kids would say about his presidential rival Mitt Romney: "Well, that's a bulls-er, I can tell." Romney senior adviser Bay Buchanan fired back , "Women in particular do not think that name-calling is an appropriate response."

Fast-forward to now. Leading Trump loyalist Nancy Mace might have a name straight from a post-war novel, but during a House Oversight and Accountability Committee hearing in the aftermath of the first assassination attempt on Donald Trump, she blasted former secret service director Kim Cheatle for her "bulls-" and being "full of s-." Far from being contrite, footage of Mace's profanities were posted on her website.

Republicans and Democrats are, as usual, divided on what's causing this spike in political profanity. Neither side wanted to be identified analysing the dark art of the political diss, but a Republican consultant says: "When Donald Trump swears, it's always referencing an issue, an opponent or a Left-wing injustice. When Kamala Harris and Joe Biden swear, they do it for the sake of it or to try to be cool."

"If you're fighting Donald Trump, you have to forcefully take him on," counters a Democrat consultant. "It's like that scene in [1987 film] The Untouchables where Sean Connery says to Kevin Costner about fighting Al Capone's gang: 'They pull a knife, you pull a gun.' That's how you defeat bullies, and Kamala Harris isn't afraid to use choice words."

Peter York, style guru and the author of new political culture wars book A Dead Cat on Your Table , thinks Harris is out to be more relatable in her rudeness. "Kamala Harris is being 'down with the people' [when she swears]," he says. "Trump is fantastically rude and mean about other human beings, but Harris comes out of a culture on the Left where she's trying to be the rock star, the feminist."

Whatever the reason, such swearing would be inconceivable in Britain, where, in 2018, the mere report that former prime minister Boris Johnson had used the phrase "f- business" sparked outrage (though admittedly the venue for his alleged outburst was supposed to be "a diplomatic meeting"). Nor did it go down well when David Cameron said, "too many twits make a t-" . And Keir Starmer quipped while opposition leader: "My dad was a toolmaker – although, in a way, so was Boris Johnson's."

"When British politicians use expletives, I think people find it shocking or pathetic, and when done openly, an apology is expected," says James Frayne, the founding partner of the opinion research agency Public First. "Because of the dominance of the BBC and the national media generally, which is averse to bad language, British politicians learnt to self-censor more than in the US.

"There seems to be now so much desire for attention on social media in the US, and so many politicians trying to get their name out there, that many will do anything to get themselves known. They [the US public] don't find it as surprising or disapproving."

Reflecting on an early stint of his career spent in New York, Frayne says: "It's ironic people in the UK find politicians swearing strange, because I found most ordinary Americans swear very little and many British people swear all the time."

Some experts foresee the exponential rise in expletives among American politicians will decline. "If we get to the point where politicians are swearing all the time, it's not going to be as useful anymore," Mohr says, "and they'll step back and stop swearing so much."

Yet for now Peter York, who has chronicled transatlantic trends for half a century, believes top US politicos should derive inspiration from the special relationship to curb their public swearing habits: "American politics needs to be more boring, more polite... and more British."