When Jane Holl Lute, the U.N.’s ambassador for peacekeeping operations, testified recently before the House International Relations Committee, she bypassed the one custom that has come to symbolize appearances before a Congressional panel: an oath.

For that matter, Lute, an American, was not even providing “testimony” to Congress. She was “briefing” Members — in this case, on the status of investigations into charges of widespread sexual abuse by United Nations peacekeepers in the Congo.

The distinction is made because the rules that govern the U.N. forbid its officials from testifying before Congress. Lobbying is also essentially prohibited.

“The U.N. does not involve itself with the internal politics of member states,” said Farhan Haq, a U.N. spokesman. Lobbying, insofar as that involves being for some things and against others, is a political process by the U.N.’s reckoning.

So what can the U.N. do to influence perceptions of its performance on Capitol Hill? Very little, directly.

And this makes the current environment on Capitol Hill especially precarious for the U.N.

The organization faces a storm of allegations, ranging from widespread corruption in the U.N.-administered Iraq oil-for-food program to a sex scandal in the Congo, where 56 U.N. peacekeepers and other employees are currently under investigation.

The international body is also expected to be at the center of a high-voltage debate over U.S. Ambassador-designate John Bolton, who is a longtime critic of the organization. And the disaffection with the U.N. could easily spill over into the Congressional spending process, where payments for dues to the U.N. must be approved.

The main reason for the U.N.’s unusual stance is the Convention on the Privileges and Immunities of the United Nations, one of the seminal agreements reached when the U.N. was founded after World War II.

The pact was intended to provide U.N. employees with the same protections given diplomats, mainly to avoid arbitrary imprisonment and other measures by dictatorial regimes.

But the same rules make it necessary for the U.N. to keep its distance from Congress — to avoid even the appearance of being too solicitous toward lawmakers. Any submission by the U.N. to Congressional demands risks setting a precedent that could be exploited by other, and perhaps less scrupulous, governments.

“We’re trying to navigate this because this is obviously not the parliament of some dictatorship,” said Deborah DeYoung, a spokeswoman for the United Nations in Washington. “This is Congress. This is not the situation the rules are specifically intended for.”

The rules, though, make it difficult for the U.N. to contend with a widespread sentiment among lawmakers that it is not just failing at its mission to do good — by, for instance, stopping the genocide in the Sudan — but has itself been a bad actor.

Sen. Norm Coleman (R-Minn.), who is leading an investigation into the oil-for-food scandal, has publicly called for U.N. Secretary-General Kofi Annan to step down. And President Bush’s nomination of Bolton has been widely interpreted as signaling a “tough love” policy toward the international body.

“We know enough already to know the weaknesses and the opportunities for reform,” said one Congressional insider who predicted a “real fight” this year over whether the United States should pay its dues to the world body.

The lobbying rules put the United Nations in a peculiar predicament as it seeks to manage a number of crises that have severely wounded the organization’s credibility on Capitol Hill.

The world body is utterly accountable to Congress — U.S. dues to the world body account for roughly 22 percent of its annual budget — but it can’t argue to Congress that the dues are worth it. That’s the job of the State Department.

“It’s sort of a balance between realpolitik — we recognize that Congress provides a lot of our funding — and respecting the needs of the other member nations,” DeYoung said.

Preserving this balance means that the U.N. provides lawmakers, at their request, with scores of briefings on any number of topics.

Just last Friday, the U.N. arranged for lawmakers to meet privately with internal and external auditors of the oil-for-food program, providing the organization with at least a brief respite from criticism that it has not cooperated with Congressional investigations.

In February, the U.N. arranged for Mark Malloch Brown, the organization’s new chief of staff, to make a special visit to Capitol Hill for a meet-and-greet with lawmakers.

But when it comes to debating the value of the U.N. itself, or of its affiliated institutions, the organization cannot play a role.

In practice, this means that while Lute does not take an oath before Congress, the State Department official who deals with Lute does. In the U.N.’s case, there’s no getting around the middle man.

“I’d certainly find it amusing and fun to grill [U.N. officials] here in hearings, but I don’t think it would serve their purposes at all,” said Rep. Jeff Flake (R-Ariz.), one of the U.N.’s toughest critics in Congress. “We hold our executive branch accountable. That’s how it should be.”

Flake said that in the next few weeks he will reintroduce legislation that would link payment of U.S. dues to evidence that the world body is willing to “come clean” about corruption in the oil-for-food program.

The legislation, which garnered 76 co-sponsors in the 108th Congress, would cut dues payments by 10 percent in the first year, if no progress is shown, and by 20 percent the next.

These are high stakes. Richard Holbrooke, a former U.S. ambassador to the U.N., told lawmakers at a hearing on Tuesday that withholding dues again from the U.N. — the first time occurred during the 1990s — would “absolutely kill the U.N., no doubt about it.”

Flake, for one, believes that the U.N. could improve relations with Congress if its top officials were only willing to show that they were genuinely interested in reform.

One way, he suggested, would be for Annan to publicly acknowledge that it makes the organization look bad when such dictatorships as Cuba and Libya sit on its human rights commission.

“If you had a secretary-general [at the U.N.] stand up and say, ‘This is a farce,’ you’d have a lot more of us in Congress who would say, ‘OK, we can work with this,’” Flake said.