Frank Zimmerman is a 60-year-old agoraphobic from Gloucester, and last year he wrote to a female MP threatening to kill her children. Like far too many women in public life, Louise Mensch, MP for Corby, often finds herself the target of hate mail and death threats, but she chose to take this one to the police, who quickly traced the violent, sexually aggressive messages to Zimmerman's computer.

Whether or not this recluse intended to carry out his disgusting threats makes no material difference to how Mensch must have felt when she opened that email. This week, Zimmerman was given a 26-week suspended sentence, one of the most high-profile such cases in recent years.

It's always annoying when someone you disagree with on nearly every count is selflessly brave. When I met the Conservative MP a few months ago, we argued about abortion rights and whether she can still call herself a feminist whilst supporting Tory cuts which will have a disproportionate impact on women (clue: not in my book). Mensch and I don't have a lot in common besides the fact that we both have vaginas and opinions, but those, as luck would have it, are precisely the qualifications that misogynist internet trolls of all political stripes and none are looking for. Abuse of women online cuts across political camps, and chatroom masturbators of all affiliations routinely confuse freedom of speech with freedom to abuse, bully and harass with impunity.

In tackling the troll head-on, Mensch has done a service not just to every woman writing and speaking in public today, but to the next generation of female opinion-makers. It only takes one person to make a stand. In cases of bullying and intimidation like this, precedent is everything, and precedent is something that, in the internet age, we often don't have very much of to refer to.

Ten years ago, politicians, journalists and celebrities might have anticipated the occasional angry letter from a reader, sometimes even a scary letter. Now anyone with a public platform can expect to face constant harassment in comment threads, via email and on Twitter, especially if they're a woman or a member of an ethnic minority.

I've had to handle threats to my family, too, alongside a daily splatter of missives that range from nastily suggestive to straightforwardly frightening. Only last week, one of these helpful people took time out of their busy day to write in with the suggestion that because I had written a short article about racism and sexism in a popular television show, a former colleague who happens to be Muslim should "slit [my] throat in an honour killing".

Maybe you feel your throat closing when you read comments like that. Some people might even wonder how this sort of abuse ever became a routine part of public conversation, something that anyone with a public platform is expected simply to "brush off". But as far as I'm concerned, it's all character-building – as long as one wishes to build the character of a paranoid human wreck.