THE WORLD FROM...the United Nations

THE blue-shirted security guards here at the United Nations are jumpier than usual these days. They go into high alert whenever reporters in search of quotes from diplomats forget to stay behind the portable guard rails.

The recent bombing of New York's World Trade Center is one obvious reason. Yet the extra caution also stems from the increasingly prominent role the UN now holds on the world stage.

Demands on the world body grow by the day. Secretary-General Boutros Boutros-Ghali wants the UN to move into preventative diplomacy and peace enforcement.

Yet even as the size and complexity of UN tasks expand, shortcomings make it more difficult to reach the new goals.

The UN is owed $2.3 billion in current and past assessments. The US, with an IOU of $846 million, is the leading debtor. A new Ford Foundation financial report notes that only 18 of the UN's 180 members were paid up by the Jan. 31 deadline. The study suggests a system of quarterly payments and a startup $400 million revolving fund for peacekeeping operations. A recent, blunt in-house report from outgoing Under Secretary-General Dick Thornburgh cites numerous management inefficiencies and suggests that th e UN bureaucracy deserves a permanent watchdog to guard against abuse.

Peacekeeping has long been one of the UN's strongest assets. Yet persuading nations to contribute troops, particularly when reimbursement is not always forthcoming, continues to be difficult. And the definition of the job is changing, with internal ethnic conflicts now more common than wars between nations. UN Security Council members, ever sensitive to the issue of sovereignty, agreed to intervene in both Bosnia-Herzegovina and Somalia only to provide humanitarian aid. Now Mr. Boutros-Ghali says well-ar med UN troops may need to enforce compliance once an agreement on Bosnia is reached. "For the sake of peace, you have to accept risk," he says.

UN credibility has suffered several blows in recent months, in Somalia, Bosnia, Cambodia.

It has been increasingly accused of partiality and timidity. Just this week Israeli officials criticized a UN relief worker for failing to help or alert troops to the stoning and shooting of an Israeli motorist in the Gaza Strip. The Khmer Rouge, which has refused to cooperate in the UN's demobilization and election plans in Cambodia, insists that the UN is siding with the Vietnamese.

Bosnian Muslims say the UN has done too little for them and should challenge Serbs who block relief deliveries. Lt. Gen. Satish Nambiar, outgoing commander of UN peacekeeping forces in the former Yugoslavia, told reporters last week that the less than 8,000 troops in Bosnia were too few to use such "muscle" on a consistent basis throughout the country.

When confronted by anti-UN protesters a few months ago in both Bosnia and Somalia, Boutros-Ghali said, "The reaction against the UN ... shows that at least the UN is being active."

Many want the UN to get tougher. "The constant humiliation of the UN ... is a humiliation for law and order," the Jerusalem Post argued in a recent editorial. "What is needed is a truly tough international intervention force."

In the end much depends on those who elect and support UN member governments that vote and supply the troops. Public opinion in many Western nations reflects a wariness to back interventions that could result in a large number of casualties.

For the UN, the question of when and where to intervene, and with what degree of force, is likely to remain a topic of hot debate for years to come.