It takes a cynical mind not to share in the achievement of Iraq's national elections. Bombs and missiles, al Qaeda threats and war fatigue failed to deter millions of Iraqis of all sects and regions from exercising a right that is rare in the Arab world. Even the U.N.'s man in Baghdad called the vote "a triumph."

On Sunday, 61% of eligible voters came out in Anbar Province, a former extremist stronghold that includes the towns of Fallujah and Ramadi. In the last national elections five years ago, 3,375 people--or 2%--voted in Anbar. The other Sunni-dominated provinces that boycotted in 2005 saw similar numbers: over 70% turnout in Diyala and Salaheddin and 67% in Nineveh, all higher than the national average of 62%. American Presidential elections rarely have such turnout.

Al Qaeda as well as Sunni and Shiiite extremist groups were defeated militarily by the surge, and this election continues the trend toward settling disputes through politics, not bombs. The remaining terrorists, far weaker and organized in smaller cells, tried hard to deter voting. Thirty-eight people died in various mortar, rocket and bomb attacks on election day. But the attackers had trouble getting near voting stations, and security in Baghdad and elsewhere was good and Iraqis brushed off these threats.

The election result itself is up for grabs and won't be known for several days. Incumbent Prime Minister Nouri al-Maliki needs to build a new coalition with skeptical Shiite and Kurd parties. Though Shiite himself, former Prime Minister Ayad Allawi attracted Sunni votes to his nationalist secular block. The Kurdish coalition may split.

But the very uncertainty about the results is a sign of democracy's advance, and the drama won't go unnoticed in a Middle East where the victories are always landslides for the ruling party. The contrast with Iran's stolen 2009 vote couldn't be more dramatic, and even Al-Jazeera ran special coverage around the clock.

President Obama deserves credit for resisting his own calls in 2008 for a quick American withdrawal. U.S. forces are considered by all sides to be honest brokers and guarantors of stability. So it was unfortunate to hear Mr. Obama, with the polls barely closed and no votes counted, promptly declare the election makes it possible that "by the end of next year, all U.S. troops will be out of Iraq."

Too much blood and treasure have been spent there to make the mission hostage to a political calendar. The nature of America's engagement will change in Iraq, but it needs to be sustained and robust. Imagine if the GIs had left Germany eight years after World War II or abandoned the DMZ in Korea prematurely.

There are dangers ahead in Iraq, including violence in the immediate post-election period. The neighborhood is still dangerous as well. The Iraqis aren't going to subject themselves to Iranian dominion, but a senior military official tells us that the U.S. now worries greatly about the "Hezbollah-ization of Iraq." Tehran gained experience exploiting sectarian divisions to make trouble in Lebanon. It has brought that to bear in Iraq, supporting Shiite extremists with arms and money, and their influence needs to be countered.

Free Iraq also represents a great U.S. strategic opportunity. As Turkey turns away from Europe (in part after having been turned away) and Iran pushes for regional hegemony, Iraq can now become a strong U.S. ally in the region if we don't abandon the field. A strong presence in Iraq gives the U.S. important leverage against a rogue regime in Tehran bent on acquiring a nuclear weapon.

We heard for years that toppling Saddam Hussein was a mistake because it empowered Iran. Now that Iraq is emerging as a unified democracy, the government in Baghdad can be a counterweight to Iran without the brutality and threat to the region that Saddam represented. Even as the number of U.S. troops declines, a sustained U.S. commitment will serve Iraq, the larger Middle East and American strategic interests.

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