The biggest political upset in modern British history was Winston Churchill’s defeat to Clement Atlee two months after the end of the Second World War. The polls accurately predicted the astonishing 12 percent swing from the Conservatives to Labour, but the science of gauging public opinion was still too novel to be taken seriously. No one imagined that the British people would turn their backs on a national icon, the man who did more than all others to save Western civilization from Adolf Hitler and the Nazis. The world was shocked and mortified.

British Prime Minister Theresa May is no Churchill and Labour leader Jeremy Corbyn is certainly no Atlee but a Conservative defeat next Thursday would be a serious contender for most shocking election result ever. When May called for snap elections on April 18, Conservatives were leading Labour by a hefty 23 points, a lead that has since been whittled down, according to a shocking YouGov poll released this week, to a meager three points. Analysts who had predicted an overwhelming landslide were still forecasting narrow Conservative victory, but they were less confident than before. May’s rapid descent in the polls could even set off Conservative panic that would make things even worse.

It goes without saying that a victory for Corbyn, a fierce critic of Israel who has yet to meet a dictator or terrorist he didn’t like, would be a harsh blow for the government in Jerusalem. It would be viewed with alarm by British Jews, many of whom regard Corbyn as an outright anti-Semite. If one wants to stretch the historical parallel, it’s worthwhile noting that while Atlee was ambivalent on Palestine and the Jewish Yishuv, his foreign minister Ernest Bevin was an anti-Zionist and anti-Semite who opposed Jewish independence and callously blocked emigration of Holocaust survivors from Europe to Palestine.

Corbyn’s surprising rise in the polls has sparked comparisons to U.S. President Donald Trump, even though the two come from opposite sides of the political spectrum. A report in Reuters on Thursday tracked Corbyn’s rapid transformation from “no-hoper to crowd-puller” who is attracting growing crowds to his campaign rallies. Many of the elements cited are echoes of Trump’s own success: Corbyn pulls no punches, he isn’t afraid of anyone, he attacks the establishment, mainstream media hate him, he’s great on social media, he’s a populist, he touches widespread disillusionment with income inequality and the breakdown of state services and speaks to the rage of younger voters who realize they won’t get ahead or live as well as their parents and grandparents.

But Trump also represents a line in the sand that separates Corbyn from May. While she was savaged for cozying up to the U.S. president and walking hand in hand with him in the White House, Corbyn has described him as a danger to the world. As prime minister, Corbyn said this week, he would consider nixing Trump’s planned visit to the United Kingdom in October. Corbyn’s rivals are also using Trump to attack the Labour leader, but from the other direction. American Jacob Heilbrunn wrote in the Spectator that Trump would celebrate a Corbyn victory, because he will be just as pro-Russia and anti-NATO as the U.S. president, only crazier. Janet Daley wrote in The Telegraph, “Jeremy Corbyn and Donald Trump represent a nihilistic assault on our democratic systems.”

Trump-bashing does political wonders in Germany as well. Non-existant in March, the gap between German Chancellor Angela Merkel’s Christian Democrats and her rival Martin Schulz’s Social Democrats has regrown to double digits because of, among other reasons, Merkel’s positioning as the anti-Trump and her crowning by Trump critics as the new “leader of the free world.” Politico reported from Berlin this week: “The American president has become the most powerful argument yet for Europeans to finally get serious about a deeper union. Widely viewed in Europe as unpredictable and dangerous, Trump is the ultimate bogeyman. That may be particularly true in Germany, a country that has long harbored a latent strain of anti-Americanism that cuts across party lines.”

Newly-elected French President Emmanuel Macron was also compared to Trump during the recent election campaign because he rose out of nowhere and attracted legions of anti-establishment enthusiasts who lapped up his populist message. But Macron, who was critical of Trump before his election, is now making his mark by becoming the most brazen Trump-thumper in Europe. While Merkel attacks Trump by implication, Macron is eager to take him on directly, like a hotheaded teen. French public opinion, which is probably even more disdainful of Trump than the German assessment, delighted in the Macron-Trump handshake showdown that turned their knuckles white and rejoiced in the red carpet switcheroo in Brussels in which Macron appeared to be approaching Trump only to veer at the last minute toward Merkel.

After Trump’s astonishing victory in November there was widespread speculation that Western European countries would be spurred to emulate Great Britain’s Brexit and to adopt the nativist anti-immigrant nationalism that seemed to have taken hold in America. Since then, the trend has actually gone the other way. The surprise defeat of Geert Wilders and his far-right Freedom Party in the Netherlands, the emphatic trouncing of Marine Le Pen in France and the dramatic resuscitation of Merkel in advance of September’s federal elections in Germany point to an anti-Trump reaction in Europe. The Anglo-Saxon bloc is going one way – Britain after Brexit, the U.S. in Trump’s footsteps – but continental Europe is closing ranks, perhaps, as Merkel and Macron hope, to regather, reform and gain strength.

The constant stream of suspicions and revelations concerning Trump’s ties to the Russians, coupled with insistent reports on Russian efforts to influence elections throughout Europe, are also taking their toll. Trump’s constant balustrades against NATO and his refusal to swear allegiance to its mutual defense clause only serve to reinforce doubts about his loyalties and to spread suspicion that he is collaborating with Russian President Vladimir Putin – and against Europe. The interests of the two sides of the North Atlantic alliance suddenly seem not just different, but contrary.

Against this backdrop, Trump’s announcement on Thursday that the U.S. would withdraw from the Paris agreement on climate change and hothouse gas emissions, signed by 197 countries, excluding Syria and Nicaragua, could prove to be the straw that breaks the camel’s back – final proof that the U.S. is abdicating its role as world leader and is adopting the isolationist policies formulated by Steve Bannon and enunciated by Trump during his campaign. The threat of global warning may be viewed by the American right as a wimpish concoction of hyperactive liberals, but for Europe and many other nations across the world it is a clear and present threat to the future of humanity.

Trump said on Thursday his move will “Make America Great Again,” but reneging on Paris is greatness only in the eyes of the fanatic American right. In Europe it will be perceived as an American knife in the back. When he got back from his first overseas trip earlier this week. Trump boasted not only of his arguably successful visits to Israel and Saudi Arabia, but also of his fantastic achievements at the NATO summit in Brussels and the G-7 meeting in Sicily. But even as Sean Spicer was singing the president’s praises in his White House briefing – including, nebbish, a line from an article written by this writer – America’s relations with Europe entered crisis mode. After his withdrawal from the Paris agreement, U.S. standing can be expected to deteriorate even further to its rock bottom 2008 levels, when the world was already fed up with former U.S. President George W. Bush and his war in Iraq. But even after 8 years of Bush, Europe had a higher opinion of U.S. leadership and the competence of its president than it does after only four months of Trump in office.

Israel sustained its own, separate disappointment on Thursday when the White House also announced that like his predecessors, Trump had signed the waiver exempting the administration from moving the U.S. Embassy in Israel from Tel Aviv to Jerusalem. Nonetheless, as in 2008, Israel will remain one of the very few countries that support the U.S. president, are grateful for Trump’s election and still prefer his policies to those of his predecessor former U.S. President Barack Obama. With the possible exception of Saudi Arabia’s fawning princes, Netanyahu has heaped more fulsome praise on Trump than other world leaders, and that’s not about to change.

A nation that prides itself on “dwelling alone” might find consolation in an isolated United States or Great Britain, but it would be misguided. A resentful America that closes itself off to the world, reneges on promises it made, shakes off international treaties it signed and turns its back on its most trusted allies – and whose president is despised and ridiculed – should scare Israel out of its wits. An America that is against the world and vice versa is a greater existential threat to the Jewish state than Israel itself, when the whole world is against it.