UNITED NATIONS — Even as the Obama administration admonishes the United Nations for an “unwarranted” pay hike for staffers, it is going to bat for the United Nations against legislation proposed in Congress that would revolutionize the way America finances international institutions and give Washington better leverage over them.

Proponents of the legislation, offered today by the chairwoman of the House Foreign Affairs Committee, Representative Ileana Ros-Lehtinen, a Republican of Florida, say that no matter how hard the administration fights against it, the current political climate presents an opportunity to rethink how American taxpayers finance Turtle Bay.

“This is the only way to create real reform, especially given U.S. budgetary stringency,” the former ambassador to the U.N., John Bolton, told the Sun. “This is the time to act,” he added. “The State Department may lobby hard” against Ms. Ros-Lehtinen’s proposal, “but the times they are a changin’.”

Mr. Bolton has long advocated reforming the way America pays its dues to the world body. He has called for Washington to finance only those U.N. units and programs it deems to advance America’s interests, rather than pay according to an assessment made by the General Assembly. His initiative is widely considered the basis for Ms. Ros-Lehtinen’s bill.

State Department officials say that voluntary-based U.N. dues would cut the amount of American contribution to the U.N. by half and undercut its world leadership. “In the long run, we would end up shouldering — by ourselves — much more of the costs and the burdens of defending and advancing vital U.S. interests,” said Mark Kornblau, spokesman for the American ambassador here, Susan Rice.

In speeches around the country, Ms. Rice has argued that the U.N. advances America’s interests, that paying for it puts America in a position to urge reform, and that it saves money.

A blue helmeted peacekeeper, she said in a February speech at Oregon, “costs a fraction of what it would cost to field a U.S. soldier to do the same job.” In another speech, at a gathering in June of an American U.N. advocacy group, she said America is “pushing real reforms that can enable the U.N. to do more with less.”

But the reform push is yet to change the U.N.

The American ambassador charged with management reform, Joseph Torsella, is complaining about how, as American government officials’ salaries were recently frozen, the salaries of approximately 4,800 U.N. staffers in New York were recently raised by nearly 3%.

“As a result of the global financial crisis, the United States government believes that no increases in either the base salary scale or post adjustment are warranted or appropriate at this time,” Mr. Torsella wrote yesterday in a letter to Kingston Rhodes, chairman of Turtle Bay’s International Civil Service Commission.

Yet diplomats here say that while America pays a larger share of the U.N. budget than any other country, its push to freeze salaries isn’t likely to succeed. Decisions involving U.N. expenditures are taken either by the secretariat or in various budgetary committees of the General Assembly, where the vote of a country that contributes little carries as much weight as that of the largest contributor.

“When you pay pittance there’s no reason you should be concerned about how the funds are used,” says the Heritage Foundation’s Brett Schaefer, who has written extensively on U.N. budgetary issues. Mr. Schaefer supports the principle of voluntary contribution, which, he says, will introduce a “market-based mechanism that is lacking” in the current U.N. assessment system.

The U.N. Charter does not define the basis on which countries should pay their dues. It only determines, in Article 19, that a U.N. member “which is in arrears in the payment of its financial contributions” loses its voting right at the General Assembly.

Rather than being constitutional, so to speak, the U.N. system of assessing dues results from a legislative process at the General Assembly, which presumably can be changed.

In the 1940s America paid nearly half of the organization’s budget. More recently the General Assembly decided to assess the dues each country owes the U.N. according to its share of the world economy, based on GDP. The final sum due is subject to negotiations, however. This has allowed America to cap its U.N. dues on a take-it-or-leave-it basis.

In the 1990s, Senator Helms successfully frustrated the Clinton administration’s attempts to pay its U.N. dues in full. Only at the end of the decade did Helms arrive at an agreement with Joseph Biden, then a leading Democrat in the Senate, to end the impasse.

The 1999 Helms-Biden compromise lowered America’s contribution to the U.N. running budget to 22% from 25%. Washington’s share of the U.N. peacekeeping budget was reduced to 25% from 30%. A decade later a new compromise raised the peacekeeping share back to 27.14%t. All told, last year America contributed $516 million for the U.N. regular budget and $1.887 billion for peacekeeping.

Now Ms. Ros-Lehtinen proposes to rethink the whole thing. The new legislation “ends the era of no-strings-attached contributions, and gives us leverage to pressure the U.N. to finally make concrete reforms,” Ms. Ros-Lehtinen said in a statement today. “Making U.N. funding voluntary will give the U.S. control over how our contributions are spent at the U.N. Otherwise, U.S. taxpayer dollars will keep being spent on the bad, the ugly, and the indefensible.”

Approached by the Sun today, Secretary General Ban declined to comment on the proposed legislation’s effect on the U.N.