WHEN revolutionaries first stormed public squares in north Africa a year ago and toppled ageing dictators, Islamist leaders were nowhere to be seen. Many feared failure or were uncomfortable with the rapid speed of change. Only belatedly did they agree to join the growing opposition. Yet when at last they contested elections, the Islamists were stunningly successful. In Egypt and Tunisia they won majorities; in Libya they are likely to follow suit and, if the Assad regime falls, they could well emerge on top in Syria too.

Despite their many differences, the successful Islamist parties share an origin in the Muslim Brotherhood, an 84-year-old Egyptian movement that combines conservative political activism with religious charity. Its organisational ties—forged during decades of clandestine opposition—extend to Palestine, Jordan and much of the Sunni Arab world, though local branches differ in outlook and strategy (see article).

The Brotherhood's growing influence worries the region's liberals and minorities, including Christians and Jews. They fear the movement's affiliates may never relinquish the power they have won at the polls and that they will impose strict Islamic rules on previously secular societies. Recent hopes of a pluralist Middle East may wane, some say. Perhaps the Islamists will try to overcome their problems at home by asserting that they have a divine mission, that Israel and the West should be demonised and that anyone who stands in their way must be suppressed. The iron-fisted rule of Hamas in Gaza is a sobering example.

Yet so far there is no sign that this is bound to happen. The Brotherhood did not expect to wield power so soon. In Egypt they resisted taking over from the armed forces until this month. Many affiliates are internally divided and unsure of what to do now that they are in power. In Egypt, the movement's centre of gravity, Islamists are split between the mainstream Freedom and Justice Party and breakaway factions. A further splintering in government is likely.

Following decades of persecution, many Islamists are deeply cautious. They may favour an Arab Palestine and the imposition of sharia law, but see these as distant projects. The immediate task is to satisfy the popular demand for growth, jobs and better services and infrastructure. The job ahead, like the expectations, is immense. And unlike the lot that have been kicked out, the new rulers face constant questioning from an awakened street.

The West can help. Vigilance is warranted in the light of the Islamist takeover after Iran's revolution in 1978-79. Groups that endorse violence ought to be kept at arm's length. But blanket antagonism toward the Brothers would be self-defeating. The Arab spring has just begun. Ruling countries is hard and reforming them will take the Brothers many years. The outside world has much to offer in terms of credit and expertise.

A helping hand

There are no guarantees of success. Some Islamists do indeed dream of a theocracy on the eastern Mediterranean. But the answer is to help ensure that reform-minded Islamists will not lose to extremists at the next election or turn more radical themselves. Engagement makes that less likely, because it would boost growth and investment, reinforce the constitutional checks that cement a pluralist society and help the design of unpopular-but-necessary economic reforms.

No doubt the West would rather deal with liberal secularists, but it cannot wish away the popularity of Islamists. Despite what some Israeli officials say, an “Islamist winter” is not imminent. But the prophecy could become self-fulfilling.