Election season has arrived in the Middle East. It seems that most of the residents of this troubled region have cast ballots in the past 12 months. Truly, what appeared impossible a few years ago is now happening before our eyes. While there is justifiable anguish about Hamas’s recent victory in the Palestinian elections and the Muslim Brotherhood’s rise in Egypt, we must not lose sight of the broader trend toward democratization. This trend provides reason for hope, as well as reason to place more emphasis on the liberal institution-building that can build a democratic tradition in the long run.

Even a cursory look around the region turns up increased democratization. The most prominent elections occurred in Iraq, where throngs of voters defied terrorist groups in three major elections last year.

Beyond that, Lebanon’s June elections brought to power a new coalition led by Saad Hariri, son of slain former prime minister Rafik Hariri. His Rafik Hariri Martyr List won 72 of the 128 available seats in the Lebanese parliament. To be sure, the continued interference of Syria and Hezbollah into Lebanon’s internal affairs poses a major obstacle. But the people of Lebanon have clearly voted in favor of independence — a point that was punctuated by this week’s demonstrations, in which more than a million Lebanese commemorated the anniversary of Hariri’s murder by demanding an end to Syrian meddling.

Saudi Arabia held its first elections since the 1960s from February to April 2005, as 178 different municipalities opened the ballot box for local elections. These were only partial elections, in which only men could vote and only half of the seats were up for grabs. But nonetheless, this was the first time that most Saudi citizens have had any input into their public lives — and this step wouldn’t have occurred were it not for the pressure that was brought to bear on Saudi Arabia following 9/11.

Egypt saw two election campaigns in 2005. It witnessed the first "open" presidential election where other candidates were officially allowed to compete against Hosni Mubarak. In practice, though, the leading opposition candidate was jailed. In October’s parliamentary elections, the fundamentalist Muslim Brotherhood won 88 seats to make it the largest opposition bloc. Like Hamas’s electoral victory, the Brotherhood’s strong showing raised concerns. If the democratization process brings Palestinian terrorists and Egyptian fundamentalists to power, should it still be supported?

Certainly the U.S. is in no position, after having peddled democracy as the solution to the region’s woes, to put the brakes on this process. Moreover, the trend toward democratization appears irreversible, at least in the short term, and neither Hamas nor the Muslim Brotherhood is likely to reverse it.

This isn’t the 1991 Algerian election, where the Islamic Salvation Front likely would have governed by the principle of "one man, one vote, one time." The Muslim Brotherhood, despite its strong showing, didn’t win a majority of Egypt’s parliament. And Hamas faces the danger of the kind of political and financial isolation that could shatter its tenuous grasp on power. Hamas has already come under great international pressure because of the murderous ideology that has long motivated the group. If it attempted to cancel elections, Hamas would almost certainly lose the support of the few remaining countries that have served as its advocates on the international stage. Because the threat of financial chaos and possible international intervention could ensure that Hamas doesn’t regain power for many years, Hamas is unlikely to believe that it could cancel elections without facing tremendous consequences.

Moreover, being elected can have a moderating effect on radical groups. Observe the Jordanian Muslim Brotherhood, a sister organization of the Egyptian Brotherhood. The Jordanian Brotherhood has served in Jordan’s parliament and cabinet since 1989, and has done so as a political party rather than an outlaw opposition group. The Jordanian Brotherhood’s participation has helped to reduce the government’s fears about the group and has led to the lifting of certain restrictions imposed on freedom of speech. More importantly, this participation has not shattered Jordan’s relative moderation.

The moderating effect of democratic politics should not be overstated: The Jordanian Brotherhood has not become a group of Jeffersonian democrats, nor is the Egyptian Brotherhood likely to completely abandon its profoundly antidemocratic ideology. But once elected, radical groups are in serious danger of losing that power that they worked hard to acquire if they don’t make compromises. Voters will remove them from office if they fail to deliver. These groups also have to deal with new areas of responsibility. Hamas’s attention can no longer be focused solely on genocidal terror campaigns; it must now be accountable for clean streets, employment and development. While Hamas has previously been able to contrast itself with Fatah through the provision of social services, it has never had to govern and administer the entirety of the Palestinian Authority.

Hamas may, of course, abandon its tepid attempts to burnish its international image in favor of all-out escalation against Israel. Thus, it’s important that the U.S. and international community not be myopic, but instead hold Hamas accountable. Failing to hold accountable any government that openly advocates and fosters violence is a clear sign of weakness — and would be even more so in the case of Hamas, which has an unmistakable history.

The trend toward Middle Eastern democratization is a double-edged sword: It can either have a moderating effect or else bring to power committed foes of the U.S. Since the trend seems certain to continue, the U.S. needs to be able to derive advantage from it. The best way to do so is through promotion of liberal institutions such as freedoms of speech, of the press and of religion.

Currently, voting in the Middle East is a Catch-22 for the voters and the U.S. Since the only safe way to criticize most Middle Eastern governments is from a fundamentalist direction, the choice at the ballot box tends to be between the corrupt rulers now in power and their Islamist opposition.

It will be much easier for the U.S. to promote these liberal institutions before hostile parties such as Hamas or the Muslim Brotherhood come to power. Thus, U.S. officials should make sure that their public rhetoric emphasizes the idea of true democracy — which encompasses not just voting, but also the vital predicates that liberal institutions comprise. Governmental human-rights reports and public diplomacy should proceed in the same manner, making clear that a true democracy is more than just a ballot. By adopting a strong policy of promoting liberal institutions, the U.S. can help the Middle East move beyond this forced choice between thieves and killers.

Mr. Boms is vice president of the Center for Freedom in the Middle East. Mr. Gartenstein-Ross is a counterterrorism consultant and attorney.