"If you haven’t been following the Democratic presidential primary closely so far, for which I forgive you, then you might have missed Marianne Williamson.

Author, activist, Oprah bezzie and general purveyor of woo-woo spiritualism to middle America, Williamson has made headlines by suggesting a “dark psychic force” has taken over the country, and claiming that she will “harness love” to defeat Donald Trump.

She’s a little offbeat, for sure, but you don’t sell millions of books without the odd spark of illumination. An incident last week, when Williamson was caught unawares on a hot mic during a TV interview, is a case in point.

“What does it say that Fox News is nicer to me than the lefties are?” she complained. “What does it say that the conservatives are nicer to me? It’s such a bizarre world. You know, I’m such a lefty. I mean, I’m a serious lefty, but … I didn’t think the left was as mean as the right. They are.”

This blunder was lapped up by conservative media. But somewhat to my surprise, I found myself nodding along. She’s got a point, hasn’t she?

I’ve drifted politically since coming to America, not to the right as such, but away from the left, into a sort of nebulous post-left diaspora. An odd move, perhaps, in the age of such a divisive president. Surely now is the time to pick a side. But increasingly I find the left, well, just a bit mean.

Increasingly I am fed up with sanctimonious Brooklyn dinner parties, where straying an inch from the path of righteousness prompts exile to the social gulag. I’m fed up with student house parties, where people go around the room asking how “white” everyone is to shame them. Increasingly I find my conservative friends more forgiving, more open to disagreement, more willing to debate without taking things personally.

All too often, the modern left is judgmental and merciless, assuming the worst rather than searching for the best, applying purity tests that erase the potential for nuance or complexity. Assuming, as Christopher Hitchens once put it, that your opponent’s lowest possible motive is in fact their only one.

This purity malady has long infected the left, but it becomes more acute in times of political extremis. If you’re not behind Corbyn, then you’re a Tory. If you’re not for Sanders, then you might as well be for Trump. If you’re not entirely good, then you are very bad. It’s this Manichean mindset that allowed The Guardian to describe David Cameron’s anguish at the loss of his young son as “privileged pain”, as it did appallingly last weekend.

Don’t get me wrong, I’m not downplaying the malevolence of the far right, nor the venom of what Hillary Clinton called America’s “vast right-wing conspiracy”. If Williamson ever actually won the Democratic nomination and ran against a Republican, well, then she would discover the meaning of mean.

But the mistake Williamson made, the one I also used to make, is to expect those fighting for a fairer, kinder world to be fairer, kinder people.

Generally they are not. Yes, their nastiness is in the service of justice and equality, but it’s nastiness nonetheless. Process matters. The journey matters. You don’t build a better world by being horrible to everyone who disagrees with you.

Ultimately we are all flawed, fallen and inadequate to the task of reaching utopia. As Immanuel Kant put it, “out of the crooked timber of humanity, no straight thing was ever made”.

This isn’t an excuse for looking at the world’s problems, shrugging your shoulders and saying “whaddya gonna do?” as too many conservatives often do. But it’s a useful starting point. For if our comrades on the left really do want to keep those dark psychic forces at bay, then harnessing a little more love might be a good place to start."