Imagine, in the wake of the arms crisis, Neil Blaney had become Taoiseach in 1970. Imagine, after his "Rivers of Blood" speech, Enoch Powell had become British Home Secretary. Imagine Ian Paisley ever becoming First Minister of Northern Ireland.
Last September one could have said: imagine after ascending the Temple Mount if Ariel Sharon ever became Prime Minister of Israel. Even for Israel's friends, this is the stuff of nightmares. Yet on February 6th, we will probably have to imagine no longer: Sharon has a commanding lead over Ehud Barak in all the opinion polls.
Ariel `Arik' Sharon is spectacularly unsuited to hold the highest political office. No one doubts his sincere love for the Jewish people and for the Zionist goal of empowering them with their own state. Nor can anyone doubt his massive contribution to the Israeli defence forces, above all in his dramatic crossing of the Suez Canal during the 1973 Yom Kippur War.
However, the same qualities which made him a peerless soldier make him a poor - some would say dangerous - politician. As Defence Minister, his handling of Operation Peace for Galilee, particularly his failure to prevent the massacres of Palestinian refugees in the Sabra and Chatila by Christian Phalangists, is incontrovertibly a black mark in Israel's copybook. His decision to prosecute that war all the way to Beirut, way beyond the 25-mile advance into southern Lebanon agreed by the Israeli cabinet as necessary to prevent PLO attacks, exemplifies his disdain for the democratic process.
These traits of Sharon's are well known in Israel, even if nearly half the Israeli electorate was not of voting age in 1982. If Sharon is elected in 12 days' time, it should not be taken as any kind of endorsement of Sabra and Chatila by Israelis, though, any more than Ian Paisley's vote in European elections should be interpreted as approval of his particular witness against the Catholic Church.
But much more of the blame lies with Barak, himself a graduate of Sayaret Ha'matkal, the Israeli equivalent of the SAS and lineal successor to Sharon's Unit 101 of the 1950s. Israel's most decorated soldier has exhibited that contempt for democratic process which is the mark of the soldier-cum-politician. He allowed himself to be browbeaten by Bill Clinton at Camp David in July 2000 into discussion of a plan to divide Jerusalem, an issue left unresolved in the Oslo Accords, the Israeli equivalent of the Good Friday agreement. He did so without any prior parliamentary or electoral mandate.
Dividing Amos Oz's "city of lunacy" might long have been on some of the Israeli Left's post-Zionist agenda but it has come as news to many Israelis. That agenda entails the idea of "de-Judaising" the State of Israel: scrapping the Star of David flag and ending the historic right of return for any Jew.
For all their pains, including the brave unilateral withdrawal from southern Lebanon, the current Labour government has seen unleashed the al-Aqsa intifada. The previously quiescent Arab population within Israel proper has detected weakness and become a risen people. No wonder many Israeli Jews have been duped by the laughable slogan: "Only Sharon Can Bring Peace".
British Prime Minister Tony Blair said in Belfast last week that we have to try to resolve the outstanding issues from the Good Friday agreement because the Middle East shows what happens when a peace process goes wrong. With elections this year, unionists in Northern Ireland find themselves in a somewhat similar dichotomy to their fellow covenanters in Israel. Will a stony face make "the enemy", the other community, lower its sights or only radicalise it further? Do unionists try to crush or to conciliate?
Despite the best efforts of prime ministers and presidents, many unionists just do not see the new Northern Ireland as a New Jerusalem, "a shining city on the hill" as Seamus Mallon called it recently. Unlike in Israel, opinion since our own peace pact has not shifted radically yet. Unionism remains publicly and painfully divided about the agreement.
Sharon has said that there cannot be a true peace in the Middle East. Most unionists are not prepared to give up hope yet. Like most Israelis they passionately want a genuine resolution of the outstanding issues in the deal they signed up to. The argument in favour of the agreement will not be clinched until they are.
But just as the Palestinians will get their just deserts with Sharon, so nationalists in Ireland must be alert to the danger of asking their co-peacemakers to extend themselves beyond what electorates can bear. If the best Dublin and London can promise is a fully-armed republican movement in government on the one hand and joint authority on the other, many moderate unionists will conclude that they are better withholding their consent to either.
Extremism will have triumphed. We simply cannot go on as we are.