For years, Egypt's Muslim Brotherhood has been taunted by its critics to demonstrate its democratic commitments. Of course, without free and fair elections in the country, it could only offer promises. But as Egyptians now go to the polls in the country's most democratic parliamentary elections in many decades, the Islamists are finally able to grasp a golden opportunity to show their democratic credentials with deeds. And that may be precisely the problem: They may be far too successful for their own good (and for Egypt's).

For many years, the Brotherhood has set a regional trend by running in rigged elections under dictatorships, using the slogan "participation, not domination." In return for the right to participate, Islamists in the Arab world assured suspicious rulers that they did not seek to replace them. In fact, they usually ran for fewer seats than they would need for a majority. Of course, there were exceptions—in Algeria in 1992 and Palestine in 2006, Islamists went for the win. In both cases, the result was civil war. Their counterparts elsewhere were explicit: they had learned the lesson that they should not push too hard too quickly.

In the aftermath of Egypt's January 25 revolution, Brotherhood leaders consistently claimed that they still took the lesson to heart. They would only seek one third of the seats; they would foreswear the presidency. And they enthusiastically pressed to give the people a chance to vote as soon as possible, moving Egyptian politics away from demonstrations in the public square and toward the polling booth. The only time they called their foot soldiers out to demonstrate was when various political forces tried to place limits on the democratic process in the form of partisan "constitutional principles" that were meant to bind those selected by the new parliament to write the country's new constitution.

Over the years in Egypt, the Brotherhood's self-restraint has set a model in the region. Even after the fall of authoritarian regimes, most Islamists' preferred outcome in the short term is an election that gives them a plurality but not a majority. Controlling the largest bloc of parliamentarians, for instance, gives them a considerable voice in the political process and allows them the opportunity to develop political skills and experience without making them appear threatening or provoking a strong reaction inside and outside the country. Such an electoral result enables the preferred Islamist strategy of gradual change and lets movements escape the burden of full responsibility for the tremendous economic and security problems of societies in turmoil.

The recent Tunisian and Moroccan elections delivered just such an outcome. Islamist parties in both countries will be in the driver's seat as Tunisia writes a constitution and Morocco experiments with limited constitutional reform.

To be sure, this strategy of demonstrating democratic credentials by working not to win elections is ironic and arguably undemocratic. In the Egyptian case, the Brotherhood sought to pursue the policy through a particularly strange and undemocratic device: it worked hard to build a coalition of political parties across the spectrum to submit to Egyptians as a single list. Instead of allowing voters to pick their representatives, the Brotherhood wanted to divvy up the seats in advance.

But in the months since the revolution, Egypt's Muslim Brotherhood has been wriggling free of the pledges to demonstrate its democratic credentials in such undemocratic ways; it is showing signs of abandoning the tendency to pull its political punches. Over the short term, it may gain many votes as a result. In the long term, it might come to regret its decision.

The go-slow approach has been undermined by a series of developments. Just weeks after Mubarak’s fall, suspicions between Islamists and other political movements began to grow. Non-Islamists grasped for a series of measures to hem in a Brotherhood movement they came to see as a rival and even a threat rather than an ally. For instance, they sought to delay elections, write a constitution first and slow the military's exit from the political scene. In private and even in public, non-Islamists could be frank about the purpose of these steps: They were designed at least in part to rein in the Islamists. The Brotherhood reacted not by seeking to reassure its rivals but by flexing its muscles, calling out its supporters for the March 2011 referendum on a set of constitutional amendments that supported the Brotherhood's call for quick elections.

Other political forces failed to build links to organized constituencies in Egyptian politics. Revolutionaries who had called hundreds of thousands into the streets made few moves toward forming political parties; nascent labor unions whose strikes had added to the revolutionary fervor did not found a working-class party. When such movements had a political demand, they resorted to the device that worked so well earlier this year—the public demonstration—and avoided the long task of party building.

The electoral law that was adopted, based on party lists submitted to all voters nationwide, also made it hard for the Brotherhood to pick and choose which seats it wished to win and which it would allow to others.

By the fall, the Brotherhood was showing signs of succumbing to temptation. Rather than stepping aside in favor of other movements in some districts, it decided to compete for almost all of them. Its idea of a grand electoral list gradually disintegrated as its partners left one by one, claiming that the Brotherhood was elbowing its candidates aside. The Islamists were not yet Vince Lombardi, but they were no longer the Marquis of Queensbury. Or to use a metaphor more appropriate for soccer-loving Egyptians, they began to play the political game more like Maradonna than Pelé.

As Egyptians begin voting, the possibility of an Islamist majority is real. Even if the Brotherhood falls short, a parliamentary alliance with Salafis and others might easily put them over the top. Observers of the voting thus far have already noted the vaunted discipline, organization and tactical acumen of the Brotherhood when it comes to politics.

Indeed, the movement's unity in the electoral realm comes as a surprise to many. Traditional strains within the movement have not been evidenced in the voting (even though they were on full display during the demonstrations that preceded the elections by mere days as the leaders refused to support the calls of some members to join the protests against the military rulers). The organizational coherence of the movement should not be underestimated; observers should never forget that Brotherhood activists engage in much squabbling but remarkably few schisms.

But the Brotherhood may one day regret its influential political status. If it does win a majority in parliament, either alone or with its remaining allies, it will find itself face-to-face with the military rulers who have shown a strong desire to retain a permanent supervisory role for themselves and an exemption from civilian oversight. The most politically astute leaders of the Brotherhood tried to avoid precisely such a situation throughout the Mubarak years. But with the president's authority exercised now by a military council, the Islamists risk falling into such a tense rivalry. The two sides squared off publicly less than a week ago overthe process for writing the constitution. The Brotherhood may find that other political actors do not rush to its side in any showdown, preferring a prolonged military role over a Brotherhood-led polity.

International actors, particularly in the United States but also in Europe, may quickly rethink their tentative acceptance ofIslamist movements in a Mideastern democratic setting.

And victory may bring other bitter fruit. The movement may have to face questions it has preferred to avoid, including how it will solve Egypt’s economic plight; how it will handle the country's rocky relationship with Israel; and how it will square its traditional commitment to religious values with its newer discovery of democracy and human rights.

An outcome like Tunisia's, where Islamists are politically unavoidable but also must reach out to others to get anything done, would serve Egypt and the Brotherhood well. The Brotherhood's electoral appetites, the military's bumbling leadership and the fecklessness of other electoral actors may be combining to undermine such a result.

Nathan J. Brown is a professor of political science and international affairs at George Washington University and a nonresident senior associate with the Carnegie Endowment for International Peace.

Image: Kodak Agfa