Fifty years ago, the historian Elizabeth Monroe published a beautifully written book with a dismissive title, "Britain's Moment in the Middle East, 1914-1956." She captured well the British interlude between two more culturally transformative powers: the Ottoman Empire and secular Arab militarism.
These days, if one has been reading the Egyptian press or talking to Egyptian liberals since the coup d'état against the country's first freely elected president, Mohammed Morsi, one might have the impression that the Muslim Brotherhood's "moment" in Egypt lasted 12 months—after a long prelude that began in the 1920s. Conventional wisdom says that the Brotherhood, founded in opposition to British imperialism and Westernizing secular dictators, has immolated itself after just a year of grossly incompetent government.
Yet grossly incompetent governance has been the norm in Egypt; popular sovereignty is new. There is no denying that countless Egyptians who had voted for Brotherhood candidates and its constitution turned against the Islamist group in massive demonstrations. There is also little doubt that many in the Muslim Brotherhood were shocked by the size of these rallies.
But it is highly doubtful that the Islamist critique of Egyptian society has been routed by marches that we now know were planned by the tamarrud (rebellion) movement and the military. The Westernization of the Egyptian poor has been in retreat for more than 40 years. The vast slums of Cairo—the broken-concrete-and-cracked-brick neighborhoods of low-rise apartments with open sewers, where only mosques and local clerics offer a sense of community and order—are hothouses for Islamism.
This is not Facebook FB +1.43% Cairo, where alienated, deplorably educated, unskilled youth express their anger online and show their own kind of community by staging street protests. Local clerics, let alone the cultish, secretive godfathers of the Brotherhood, do not command Cairo's slums—though local imams and popular preachers are certainly more influential than any representative of a state institution. The faith, fused to politics by tradition, profoundly matters among the poor and the lower middle class.
In these precincts the Egyptian army, the security services and police—all unreformed since the fall of Hosni Mubarak—are viewed suspiciously, if not with hostility. The newfound love affair between the army and Egypt's secular liberals, who in a year's time came to the conclusion that they needed the military to check Islamist power, will likely do nothing to diminish the skepticism that Egypt's devout have for army officers and their associates.
Mr. Morsi obviously didn't handle his short term in office well. He alienated allies needlessly, including powerful fellow Islamists in the Nour Party. But many of Mr. Morsi's problems were either orchestrated or encouraged by the army, security services and the police (the sometimes fractious triad of the Mubarak-era police state) and by the secular business elite.
Many of Mr. Morsi's problems will now be confronted by the army-appointed government and any "democratically elected" administration that may follow. Saudi cash has been pouring into Cairo since the coup—the Saudi royal family fears the Brotherhood's populist Islamism—but the money won't last forever. An economic judgment day is coming, and it is by no means clear that the secular crowd will do any better than the Morsi government did.
They may well do much worse. Economic revitalization in Egypt won't happen unless the poor accept the pain that will come with shrinking the country's unsustainable subsidies and state-owned enterprises. Buying in now, after the coup, will be much more difficult for those who support Islamist causes.
It also isn't clear that the secular crowd is economically more adept than the Muslim faithful. Socialism has been a hard-to-kick drug for Egypt's legions of nominally college-educated youth, who came of age expecting government jobs. Capitalism has probably got firmer roots among devout Muslims, where Islamic law teaches a certain respect for private property.
The Muslim Brotherhood's senior leadership may not recover from the coup. After all, Egypt's Islamists are not immune to Western imports of individualism and a distaste for hierarchy. The Salafis of the Nour Party took nearly 30% (much more than any secular party) of the parliamentary vote that was scrapped last year. These Salafis are new-age fundamentalists, who may gain at the Brotherhood's expense.
But only the deluded, the naïve and the politically deceitful—Western fans of the coup come in all three categories—can believe that Islamism's "moment" in Egypt has passed. More likely, it's just having an interlude.
Mr. Gerecht, a senior fellow at the Foundation for Defense of Democracies, is a former CIA Middle Eastern specialist. This op-ed is adapted from a forthcoming article for the Hoover Institution's online publication, The Caravan.