Tomorrow is Secretary-General Ban’s 100th day in office, but he is far from victory in the battle to rein in the U.N. bureaucracy.

Long ago, back in South Korea’s era of high infant mortality, a baby who survived its first 100 days had reached a great milestone. Thus, in the Korean tradition, the completion of the first 100 days of any human enterprise is said to call for a celebration. As in the case of a newborn, if a newly opened store, a budding love affair, or a democratically elected government made it through three-and-a-half months, it was said to have a bright future ahead.

As he took office, Mr. Ban sent several good signals. Departing from his predecessor’s legacy, he announced he would immediately fill in a financial disclosure form and make it publicly available. He acted on both in short order, calling on other officials to follow his example.

Kofi Annan was dragged kicking and screaming to fill in his own financial disclosure. As secretarygeneral, he argued that he should not be obliged to abide by the same rules he had enacted to make his administration look more transparent. And the rule, he then added in a lawyerly way, requires only filing the form with an auditing firm, not making it public.

This was the perfect illustration of Mr. Annan’s Turtle Bay, where top executives, who constantly cast stones at world leaders’ behavior, failed to notice the precarious structure of their own glass house. Mr. Ban came from a government culture where officials disclose finances because they must be accountable to the taxpayers that provide their salaries.

Leading by example is not always a recipe for success, however. U.N. spokesmen say “98%” of all the top executives who are required to do so have handed in disclosure forms. This means some have not, but to date, no one has been disciplined for failing to file the form.

And while Mr. Ban said he would not compel anyone to follow his example, he did encourage officials to be “as transparent as possible” and to “volunteer information.”

Instead, the entrenched U.N. culture is well illustrated by the undersecretary-general for management, Alicia Barcena. She has “no problem” about making her own finances public, she said recently at a brief press conference, but “personal issues” such as inheritance or divorce may prevent others from doing so. And so, as of yet, not any of the top officials — including Ms. Barcena — told the public anything about the assets they possess.

As this episode illustrates, Mr. Ban’s institutional instincts are sound. But calling for change is not enough if the person whose job is to enforce the changes is committed to the old ways. Ms. Barcena, a leftover from Mr. Annan’s administration, is a believer in that leadership’s notion that Turtle Bay’s secularly divine mission in the world is too important to allow the world a peek into the internal workings of the United Nations.

Mr. Ban has spent a lot of political capital on enacting institutional changes such as splitting the behemoth Department of Peacekeeping Operations in two. But how different can the new DPKO be if its leader remains Jean-Marie Guéhenno, who has been its chief for over a decade?

The most important revolution enacted by Mr. Ban so far has little to do with institutional tweaks but with a subtle-yet-unmistakable change in the tone of the political statements made by the secretariat. The reason for that is a personnel change at the top.

An American, Lynn Pascoe, is clearly becoming one of Mr. Ban’s most valuable aides, and in time, his appointment as undersecretarygeneral for political affairs may prove to have been a turning point. In this department, too, the recent decision not to renew the contract of the Middle East envoy, Alvaro de Soto, a rigid U.N. traditionalist, will succeed only if a more creative person is named to replace him.

In his first 100 days, Mr. Ban showed that his instincts are sound and that he is capable of sticking to his guns even when troublemakers at the General Assembly act against him, as they did by opposing the plan to split the DPKO. But if he wants to really change Turtle Bay, Mr. Ban will need to throw more of the old rascals out and infuse the organization with some new blood.

After two overseas trips, Mr. Ban seems enamored with the trappings of diplomacy, but even if Turtle Bay one day becomes a real agent for change in the world, it cannot do so before significantly changing itself.

bavni@nysun.com