The president of the United States threatened this week to commit genocide against Iran. As Israel engages in continued bombing in Lebanon, killing more than 200 people in a single day, that fact must never be scrubbed away, not least because there is no guarantee the threat will not be revived. But as we descend towards the abyss, we need to understand where our fall began.

“A whole civilisation will die tonight, never to be brought back again,” Donald Trump wrote on Tuesday. Just over a year ago, he announced: “A civilisation has been wiped out in Gaza.” The connection is not hard to trace. Trump knew Gaza had been razed by Israel, insisting it was “not a place for people to be living”. When he joined forces with the perpetrator of that genocide in an illegal war on Iran, the apocalyptic rubble of Gaza became a template.

For two and a half years, western politicians and media outlets normalised Israel’s wholesale shredding of international law. Opponents of the genocide in Gaza warned this would unleash a boundless violence. They were right.

The US-Israeli war on Iran began with the mass killing of 175 people, most of them schoolgirls, in the city of Minab. When it happened, there were hardly any outraged front pages, nor nearly enough strong denunciations of the US from western leaders. But what did we expect? The west had already normalised the killing of more than 20,000 Palestinian children. Many were incinerated in their beds; others deliberately shot in the head, chest and genitals, according to western doctors who served in Gaza. Now 763 Iranian schools are reportedly damaged or destroyed – but did the west not facilitate the same fate for almost every single school in Gaza?

According to the Iranian Red Crescent, 316 medical centres have also been severely damaged or destroyed, but did the west not normalise the Israeli attack on every hospital in Gaza and the killing of at least 1,722 health workers?

Trump threatened to destroy Iran’s power stations. Recall how Israel’s then defence minister, Yoav Gallant, announced “no electricity, no food, no water” for Gaza within days of the assault beginning, justifying it on the grounds that Israel was fighting “human animals”. When Trump was challenged that attacking critical Iranian infrastructure would be a war crime, his answer was strikingly similar: “They’re animals.”

Many now expressing horror at Trump’s genocidal rhetoric were silent during the torrent of such statements from Israeli leaders. Leaders such as the Israeli president, Isaac Herzog, who declared “an entire nation out there that is responsible”. Or the Israeli general who openly described “the citizens of Gaza” as “human beasts” who would be “dealt with accordingly”, which included getting “hell”. There was no outrage then, so why be surprised when Trump threatens that Iran will be “living in hell”?

Trump openly defies international law – but that law was already in ruins. Israel committed war crimes in Gaza with western-supplied weapons. Since the international criminal court issued arrest warrants for Israeli leaders, many western states have refused to honour them. Its judges were put on a sanctions list by the US and abandoned by their own European governments.

Most western leaders ignored Israel’s genocidal intent altogether. Many western media outlets gave it little or no coverage, and failed to name it. And when the intent became reality, it too was normalised.

How did western politicians and media outlets bring us here? In the case of our politicians, there are many explanations. Some believe Israel serves western strategic interests. “If there were not an Israel, we’d have to invent one,” as Joe Biden put it in 1986. And then there’s the power of lobbying: in the US, for example, the American Israel Public Affairs Committee lobby has spent $221m since December 2021, including on huge donations to political campaigns.

Most of our media outlets have long echoed official western foreign policy talking points. But why did so few commentators in the west speak out? Did they not regard Palestinian lives as equal in value? Perhaps that’s why no atrocity, however grotesque, provoked the emotional response I believe it would have if the victims were people they identified with: whether it be the massacre of starving civilians as they sought aid, panicked children blown apart by tanks or detainees reporting being sexually abused.

Much of it was cowardice. Journalists have told me they feared speaking out would imperil their careers. They might lose their jobs. Freelancers might lose commissions. Broadcasters might not invite them on to panels. They might get falsely smeared as antisemitic and terrorist supporters.

These were rational fears – this has happened. Few mainstream journalists spoke out from the start. I know that many of those who did, in Europe and the US, knew they were risking their careers. But what price cowardice? What is the cost of prioritising careers and reputations over the lives of countless Palestinians as they are bombed, shot and starved?

The price of what western politicians and media outlets have done – and not done – is being paid now by Lebanese civilians. This week, Israel launched 100 airstrikes in 10 minutes across Lebanon, tearing through homes and civilian infrastructure in the knowledge that no meaningful consequences would follow.

And the price will continue to be paid – in years of slaughter and devastation to come. When barbarism is normalised so completely, when the line between the permissible and the unthinkable is erased, it cannot simply be redrawn. What was once unsayable becomes routine; what was once unthinkable becomes policy. There is no clean return from that. The horrors ahead will not be confined to the Middle East. And when the same politicians and media voices express their belated outrage, remember: they helped make this world.

• Owen Jones is a Guardian columnist

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