‘Allah is our objective; the Prophet is our leader; the Quran is our law; Jihad is our way; dying in the way of Allah is our highest hope.” So goes the motto of the Muslim Brotherhood.

What’s extraordinary about this maxim is the succinct way that it captures the political dimension of Islam. Even more extraordinary is the capacity of these five pillars of faith to attract true believers. But the most remarkable thing of all is the way the Brotherhood’s motto seduces Western liberals.

Readers of this paper are familiar with the genesis of the Muslim Brotherhood: its establishment in Egypt in 1928 by Hassan al-Banna; its history of terrorism; its violent offshoots such as al Qaeda, Lashkar-e-Taiba, Jamait Islamiya, Islamic Jihad, Hamas and others across the Muslim world. Readers may also recall the brutal crackdowns on the Brothers by autocratic regimes in the Middle East—particularly in Egypt under Nasser and in Syria during the Hama massacre of 1982.

As a result of these crackdowns, the Brotherhood renounced violence in the 1970s (after Nasser’s regime executed the Islamist philosopher Sayyid Qutb in 1966) and started a gradual process to participate in conventional politics. This renunciation—and the Brotherhood’s involvement in the Egyptian uprising, neither violent nor dominant—has prompted some commentators to encourage the American government to engage with the Brothers as legitimate partners in Middle Eastern affairs.

Like a drug addict after years in rehab, the Brotherhood is now regarded as clean. Precisely because of its troubled past, so the argument goes, it can be counted on to help lead the people of Egypt into a new era of political reform.

These commentators claim the Brotherhood will be a better partner for the U.S. than the ousted President Hosni Mubarak because it is a grass-roots movement with a significant civic and economic role in Egyptian society. They liken the Brotherhood to Turkish Prime Minister Recep Tayyip Erdogan’s AK Party, which is widely admired in the West for its moderate Islamism, offering Turks the attractive combination of economic development and religious identity. According to this view, moderate Islamism is like Christian democracy in postwar Western Europe.

In recent days, Essam El-Errian and Tariq Ramadan have expressed such views in the New York Times and the Herald Tribune. A member of the Brotherhood’s Guidance Council, Mr. El-Errian wrote that his organization has an “unequivocal position against violence” and aims “to achieve reform and rights for all.” According to his account, the Brotherhood has no desire to play a dominant role in a new government, and it won’t put forward a candidate for the presidency.

Mr. Ramadan, the grandson of the Brotherhood’s founder, predictably painted the group as peaceful. If it had ever done anything to make anyone doubt its peaceful credentials, he argued, it was the fault of the oppressive regimes supported by America and other Western powers.

Neither Mr. El-Errian nor Mr. Ramadan mentioned that the Muslim Brotherhood’s motto is still in place, let alone its implications. At least Mr. El-Errian admitted that the movement does not want a Western-style secular liberal democracy, since such democracies reject the role of religion in public life.

These apologists for the Muslim Brotherhood are targeting two audiences. The first is the small but influential liberal elite in the U.S. and its larger counterpart in Europe, which has never been comfortable supporting the likes of Mr. Mubarak and would love to believe in a touchy-feely moderate Islamism.

The second audience is the mainly young people who initiated the uprising and have kept it going with social-networking sites and other modern media tools. Young people in the streets of Cairo cannot help but be attracted to the force that has been the most tenacious and consistent opposition to the hated dictator. And they are mostly Muslims, after all.

Yet the youth also are not entirely ignorant of the drastic changes that Islamists impose on the societies that they end up governing—banning alcohol, music, movies, nightclubs. Muhammad Akef Mahdi, one of the supreme leaders of the Brotherhood in Egypt, has said in various interviews that the Brotherhood wants to purge the press of un-Islamic content and to seek conformity between the cinema and theater and the principles of Islam.

The Brotherhood’s political skill is formidable and it seems to be achieving its goals—namely, insistence from gullible Westerners that there should be elections as soon as possible and at least tacit support from young Egyptians whose votes it will need to win.

Rather than running op-eds by the likes of Mr. Ramadan, the Western press would better serve Egyptians by exposing the Brotherhood’s hidden agenda. Due to the limits on press freedom in Egypt, many educated Egyptians and other Arabs depend on the Western media for news and analysis. To deny them close scrutiny of the Brotherhood’s past and future plans is unforgivable.

Instead of simply pushing for elections at the earliest opportunity, Western commentators should be pushing for more time—above all, to allow the drafting of a new Egyptian constitution. Such a constitution would introduce checks and balances, eliminate the one-party system, and guarantee the protection of human rights. In particular, it would safeguard Egypt against the imposition of Shariah law.

True, constitutions can be discarded by tyrants or religious fanatics if they assume power. But the introduction of a well-designed constitution would make it harder for them to do so. It would also make it easier for the U.S. and other foreign observers to ensure that any future elections are free and fair.

Anyone who believes that a truly democratic outcome in Egypt is the real goal of the Muslim Brotherhood has failed to understand—or purposefully ignored—the group’s motto.

Ms. Ali, a former member of the Dutch parliament, is the author most recently of “Nomad: From Islam to America—A Personal Journey through the Clash of Civilizations” (Free Press, 2010) and is a resident scholar at the American Enterprise Institute.