A consistent theme from the earliest days of the Trump administration was the intent to lower the amount that America pays for United Nations peacekeeping.

During her confirmation hearing, Ambassador Nikki Haley repeatedly said that the U.S. contribution to the peacekeeping budget was too high and should be lowered to 25 percent. The current U.S. budget is at 28.5 percent. President Donald Trump’s budget blueprint also stated that “the U.S. would not contribute more than 25 percent for U.N. peacekeeping costs.”

Congress seems to have gotten the message based on the 2017 budget that enforces U.S. law, capping U.S. contributions at 25 percent of the U.N. peacekeeping budget. It also reduces appropriations by about $500 million compared to 2016.

Congress should be applauded for deciding to enforce U.S. law and policy that dates back to the 1990s. But this is only the start of the process. The tough task of changing the U.N. scale of assessments lies ahead and will require a collaborative effort in New York, in foreign capitals, and on Capitol Hill.

But first, Americans should care about reducing America’s peacekeeping dues for two reasons:

1.) The U.S. is paying far more than other states. U.S. demands for lower U.N. assessments are nothing new. Dating back to the founding of the U.N., U.S. politicians were opposed to being held excessively responsible for the expenses of the organization and used various means, including withholding, over the past 70 years to lower America’s U.N. assessment.

The issue of funding for U.N. peacekeeping became prominent in the early 1990s after an unprecedented surge in the number and size of peacekeeping operations dramatically increased U.S. payments. As President Bill Clinton stated before the U.N. General Assembly in 1993, “United Nations operations must not only be adequately funded but also fairly funded … [O]ur rate should be reduced to reflect the rise of other nations that can now bear more of the financial burden.”

In 1994, Clinton signed a law capping U.S. peacekeeping payments at 25 percent of those expenses. Because the U.N. charged the U.S. more than 30 percent at the time, this led to large arrearages. The resulting financial stress forced the U.N. and the other member states to agree to a new peacekeeping assessment formula and other reforms in return for payment of U.S. arrears as stipulated in the Helms-Biden legislation.

Although the U.S. rate did not go down to 25 percent immediately, Ambassador Richard Holbrooke testified to the Senate in 2001 that “[t]he U.S. rate will continue to progressively decline, and we expect that it will reach 25 percent by roughly 2006 or 2007.”

The U.S. paid its arrears, but that goal was never reached. By 2009, the U.S. share had fallen to less than 26 percent, but under the Obama administration the trend reversed and the U.S. assessment climbed.

Currently, the U.S. peacekeeping assessment is about 28.5 percent. This is more than 185 other U.N. member states combined and more than all of the other permanent members of the Security Council combined.

Although the U.N. assessments are supposed to be based on the “capacity to pay,” current disparities in assessments have some governments paying $8,000 for U.N. peacekeeping while the U.S. is charged over $2 billion. Although it is reasonable for wealthier countries to pay more, the privilege of U.N. membership should cost more than an inexpensive car.

Beyond fairness, this situation is not healthy for the U.N.

When countries pay a pittance to the U.N. budget, it undermines their incentive to fulfill their oversight role and make sure that contributions from all countries are used well and not squandered.

2.) Cost savings. Although it does not sound like much, the 3.5 percentage point difference between 25 percent and 28.5 percent of the U.N. peacekeeping budget actually translates into hundreds of millions of dollars each year.

Under the current peacekeeping budget of $7.87 billion, America would save more than $270 million. The failure to reduce the U.S. peacekeeping assessment to 25 percent by 2007 as Holbrooke promised has cost American taxpayers well over a billion dollars. This is because Congress has repeatedly adopted legislation temporarily overriding the 1994 U.S. law capping U.S. payments.

While the peacekeeping budget will hopefully go down under Haley, who has made clear her intent to review the size and mandates of U.N. operations and close unnecessary missions, the demand for expensive U.N. peacekeeping missions will continue into the foreseeable future. Thus, pressing the U.N. to reduce America’s peacekeeping assessment has the potential to save American taxpayers billions of dollars.

U.N. peacekeeping is important and can serve U.S. interests. But it also serves the interests of other U.N. nations and it is not unreasonable for the U.S. to ask them to step up their commitment—especially since the U.S. would still be paying 25 percent of the bill.

But convincing other governments will not be easy. Cajoling U.N. partners is unlikely to be successful without additional pressure.

How do we know this? Because the pro-U.N. Obama administration pursued that course unsuccessfully for eight years. The Obama administration came into office insisting that using financial leverage to press for U.N. reform was counterproductive.

It worked with Congress to pay U.S. arrears to the U.N. and adopted a conciliatory diplomatic approach to lower the U.S. peacekeeping assessment via direct diplomacy with other governments in New York and in the U.N. Committee on Contributions.

The result? America’s peacekeeping assessment was raised repeatedly.

This happened for two reasons.

First, the U.N. scale of assessments is a zero-sum game: In order for the U.S. assessment to fall, the assessments for other countries must rise. Thus, pressure must be applied to overcome the disincentive of other countries to pay more, which the Obama administration eschewed.

Second, the U.S. actions signaled to other countries that it was not serious. Every time the Obama administration and Congress appropriated funds over the 25 percent cap in order to avoid arrears, the other member states saw that the U.S. was not committed to the limit, and would go along with increased peacekeeping assessments.

There are a number of paths to offset the reduction in America’s assessment, but all involve costs for other nations.

To avoid the failure of the past eight years, a different approach is necessary. The new scale will be debated and adopted over the next 18 months. Other member states and the U.N. leadership need to know now that the U.S. is serious. Thus, the decision to enforce U.S. law capping peacekeeping payments at 25 percent comes at a perfect time to supplement America’s diplomatic efforts.

The short-term result will be arrears. But, as we saw in the 1990s, leveraging payment of arrears in return for reform of the U.S. assessment can be an effective tactic when combined with a determined and creative diplomatic effort in New York and by our diplomats around the world.