Sometimes it takes just a single word. This particular word, used three times in a newspaper article, offered a glimpse of an unwelcome future - one in which Israel is seen all but universally as a pariah state.

It appeared in a Daily Express report on Stephen Hawking's decision to join the academic boycott of Israel. The article focused on what it called the "barrage of vile abuse" and "disgusting" jokes aimed at Hawking by defenders of Israel on social media, quoting the "sick user" who posted that "the antisemite Stephen Hawking can't even wipe his own a**," another who said "He should die already!" and a third who wrote that the physicist was "also crippled in the head".

Appalling as they are, none of those remarks includes the word that struck me. For the Express report referred to Hawking's decision to join the boycott of "the Israeli regime," which is why he was staying away from a conference hosted "by the regime's president," Shimon Peres.

Regime. That's the word reserved for Iran and North Korea. Yet here it was applied to Israel, not in a rant from George Galloway or a fiery polemic in the left press, but in the Express, a paper of the centre-right with little interest in foreign affairs.

As it happens, the word was changed in later versions of the online story (after what I'm told was a very angry phone call from the Israeli embassy to the reporter involved). But the memory of it lingers because it shows how things could end up - with Israel shunned and vilified, not just by activists and campaigners, but by the mainstream.

The word used is one reserved for Iran and North Korea

As I understand it, no anti-Israel animus drove that story; that's not really the Express' thing. The angle instead was appalling abuse directed at a British national treasure. If that abuse had come from opponents, rather than defenders, of Israel, the Express would have condemned it just as vehemently.

But the sad truth is Hawking was speaking out against Israel, not for it. And his status as a national treasure affects how that stance is perceived, making it instantly mainstream rather than fringe or radical. It's too early to tell if his decision will prove a tipping point for the boycott movement, but it could. As I never tire of pointing out, quoting scholar Ze'ev Mankowitz, people don't believe in ideas - they believe in people who believe in ideas. Many people around the world believe in and respect Hawking and will, as a result, now think that perhaps they, too, should boycott Israel.

Avowed opponents of the boycott - and I am one of them - should fear this shift, rendering anti-Israel sentiment less Palestine Solidarity Campaign and more Blue Peter Appeal, a view that is not controversial, or even that political, but apparently held by all right-thinking people. Once that kind of consensus settles, it can be impossible to shift.

Those who resorted to such vile insults against Hawking were obviously wrong. But so, too, were those who, in more elegant language, cast Hawking as some congenital Israel-hater. The painful truth is that Hawking has a long track record as a friend of Israel; he had visited the country four times, given the red-carpet treatment when he went in 2006. But now he has had enough.

Rather than slamming him, those who wish the best for Israel should contemplate what Hawking's move means - that unless the country changes course, ending an occupation 46 years old this week, then Hawking's action will become the norm. The great physicist has allowed us a peek inside the black hole inhabited by the world's pariah nations. That glimpse alone should make us recoil.

Jonathan Freedland is a Guardian columnist