BAGHDAD – The city was eerily quiet on Saturday. There were no reported terrorist attacks. Zero. Earlier this year, it wasn’t unusual to see several hundred a day.

But on Saturday, from atop the Memorial to the Unknown Soldier – built by Saddam Hussein during the Iran-Iraq war in the 1980s – all seemed well. There was smoke in the distance, but that was from a refinery to the south. Perhaps the memorial’s giant dome, meant to represent a traditional warrior’s shield, was extending its protection over Baghdad.

When you’re part of a press delegation to Iraq organized by the State Department, much planning goes into showing the positive side of U.S., coalition and Iraqi efforts. But even the best PR person can’t plan an attack-free day.

No, that’s the result of a monumental years-long effort by hundreds of thousands of U.S. forces and even more Iraqi soldiers and police. It comes after great sacrifice, much grieving, and billions of dollars spent.

In part because of those costs, there will be no celebration. Some are grateful, but when discussing the changes here, one word comes up over and over: fragile. Yes, the developments of the last year are promising, but this isn’t over. The situation is fragile.

You hear the word in briefing rooms inside the Green Zone, on the streets of the struggling Doura market area in Baghdad’s Rashid district, and in last month’s Defense Department report: “Measuring Stability and Security in Iraq.”

There are several reasons for the improved security:

The surge that not only increased the number of U.S. troops, but also implemented a counterinsurgency strategy that focused on protecting the people of Iraq.

The huge strides made by Iraqi forces during the last year in training, professionalism and battle-tested readiness, as evidenced by engagements from Basra to Mosul.

The commitment of the Shia-led government to reward mostly Sunni irregular forces such as the Sons of Iraq, whose cooperation helped secure the peace in many parts of the country. This month the government began making good on its promise to bring some of those fighters into the security forces, while providing jobs or education for others.

With so much having gone right – finally – why the worries about fragility? Here’s a short list of concerns heard over the last few days:

The ongoing fight against al-Qaida in Iraq, which tenaciously maintains a foothold in places such as Mosul and Diyala, even though it was driven from other cities and provinces in the last two years.

Maintaining security gains, both in areas under coalition control and those turned over to Iraqis. Too often in this war, as progress in security was made, U.S. forces pulled back and gains evaporated as al-Qaida or Shiite militias stepped in to fill the void.

Gaps in building and equipping the Iraqi security forces. Though much improved, the Iraqi army and police will need a few more years to develop logistic, support and other capabilities before they can go it alone.

Lack of capacity for self-governance among Iraqi officials. After many years under a dictator, they need help with the basics: budgeting and decision-making processes, distribution of resources, elimination of corruption, even paying soldiers on time.

Needs in infrastructure and basic services. Communities devastated by sectarian violence must figure out how to rebuild, bring people back, and develop economically with the help of the central government.

It’s tempting to look at the successes of the last two years and say: “That’s enough. Let the Iraqis take it from here.”

But if Iraq isn’t ready to keep the pressure on al-Qaida and other extremists, and those groups can roll back security gains, governmental and political progress will be lost, too. Officials will be focused on survival, not public service.

There will be a drawdown of U.S. forces, no question. In fact, it’s already happening. But how we leave and what we leave behind will be just as important as why we came, as the U.S. ambassador to Iraq, Ryan Crocker, often says.

A day free of attacks in Baghdad doesn’t mean all is well. It is a time to say a prayer of thanks for those who made it happen – and then get back to work to make sure more days like it will follow.