Earlier this month, the foreign affairs committee held an evidence session into the use of strategic lawsuits against public participation (Slapps). Catherine Belton amended references to Roman Abramovich in her book Putin’s People after he sued her and her publisher for defamation. She had described the aggressive tactics often used by some British legal firms. Tom Burgis, author of Kleptopia – who recently had a libel case against him brought by the Eurasian Natural Resources Corporation (ENRC) thrown out by a judge – said, of the way some London law firms behave: “You are cast as the most monstrous, scheming, corrupt version of yourself.” Slapps are one of those things that nobody used to talk about, but suddenly everyone wants to talk about. In January, David Davis and Liam Byrne spoke in the Commons of the various ways journalists have been put on mute by litigation from big-money players. Byrne, on poetic form, said the journalists’ dictum of “follow the money … is now being smothered, suffocated and strangled in courts by allies, associates and friends of President Putin”. Defamation is one of four areas of law that the wealthy typically use against investigative journalists. The others are privacy, data protection and – comically – harassment. It is very hurtful to a billionaire’s feelings when people bang on and on about where their money came from, and which of their enemies mysteriously died. (Just this weekend we’ve read about how England’s legal system can have a chilling effect on journalism in the Sunday Times’ remarkable piece on the disgraced former MP Charlie Elphicke.) Suing a troublesome journalist can be a win-win for those with deep pockets. If you go after the publisher alone, they may be tempted to settle out of court: the expense of fighting a case to trial is a powerful deterrent. If you go after the individual alone, you can effectively silence them for the duration of the case; in victory, you can silence and probably bankrupt them; even in defeat, all you’ve lost is a fraction of your vast, inexhaustible wealth. An expensive lawsuit can leave an author isolated, as all those who would naturally publicly support them are themselves terrified of getting sued. Yet even knowing all that, there is a side dish to the legal proceedings that has, until now, also silenced civil society: relentless ad hominem attacks and insinuations that the writer is a bad, discredited person. These tend to come from commentators, keyboard warriors and social media users, both named and anonymous. The best-known victim of such a smear campaign – in which legal action can encourage an avalanche of social media slurs, which are then picked up by mainstream commentators – is the Observer journalist Carole Cadwalladr, who is being sued for defamation by Arron Banks. Unesco did a forensic analysis of the “networked gaslighting” she has received online, examining more than 2m English-language tweets about her; it found that 55% of all the abuse was personal, “highly gendered and designed to hold her up to ridicule, humiliate, belittle and discredit”. A similar piece of work was undertaken by the International Center for Journalists about Maria Ressa, the Nobel peace prizewinning Filipino-American founder of a news site in Manila, and its findings were near identical – though with additional racism. We often get mired in questions about how many of these online abusers are real people, and how many are bots, particularly given the very similar wording across screeds of output. The much more important issue is the migration of the abuse from insular online spaces to the wider public sphere, which is what makes the discrediting effective. Certainly, when broadcasters such as Andrew Neil repeat tropes like “mad cat woman”, that has a powerful impact, amplifying and legitimising abuse that previously sounded totally unhinged. But the role of the bystander – which is to say, all of us – is equally important and more complicated. Most people can see a conflict and have a good instinctive read on who’s David and who’s Goliath, but don’t have time for a deep dive on matters that are technical and opaque. A charge by one side that the other is mad operates like a dispensation; there is no David or Goliath: only a crazy person howling at nothing. You no longer have to trouble yourself about who’s telling the truth, you can just spectate as it all plays out. Surely time will tell which is the rational actor? Misogyny, which always seems so baggy and old-hat as a concept, is actually a state-of-the-art precision tool in the battle between investigative journalists and campaigners, and the forces of corruption. It is quite difficult to make the case, without evidence, that any given individual is mad – yet it’s much easier, almost too easy, to make it land if that individual is female. It’s not new – “A little bit nutty and a little bit slutty” was the famous smear used to discredit the US lawyer Anita Hill when she made a harassment claim in the 1990s. What is new is that it has been systematised, invested in and networked, so that any woman investigating anything should expect doubts to be raised about her sanity. In the immediate term, we need better general inoculation; or to put that another way, if someone tells you a woman is mad, just don’t buy it. Zoe Williams is a Guardian columnist