Third, be ready to walk if those redline conditions are not to be met. Here, it is vital to show unwavering resolve in the face of the inevitable resistance that will come from the defenders and beneficiaries of the status quo.

To demonstrate that unwavering resolve, we had to be fully prepared to exit the postal union. So even as our negotiations unfolded, we prepared to exit the agreement without disrupting international mail, particularly election and military mail. Through such meticulous preparations — which we made clear publicly and through diplomatic channels — we clearly signaled there was no hesitation in our threat to walk.

Fourth, change is rarely achieved by going it alone. Early in the negotiations, we engaged with the union’s leadership, even as we identified partners we could work with to win the reform we wanted — countries like Brazil, Canada, Iceland, Norway and South Africa were all similarly harmed by the status quo. Through intense negotiations, we built a coalition of pro-reform countries, founded on the principle that what is fair to American businesses and workers is also fair to the world.

Finally, hit back hard on those who opposed the needed reforms. An obvious antagonist was China, the biggest beneficiary of the distorted system. It tried to bully countries, particularly in Africa, to which it had lent considerable sums of money. We countered that there was much more to lose if the United States exited the postal union — and much to gain by working with a democracy rather than an authoritarian state.

A more subtle problem lay with several countries like Germany, the Netherlands and Britain. At the Geneva meeting, their powerful postal systems sought to advance narrow rent-seeking interests that clearly deviated from the broader strategic relationships the United States has with these countries. We countered by bringing this divergence to the attention of higher-ranking government officials — and putting the issue in its broader strategic perspective.

Collectively, these five lessons represent a new kind of Trumpian diplomacy that achieves results while advancing the interests of American businesses and workers across the globe. Through gritty determination and creative diplomacy, we clearly have the ability to remake and revitalize many of the antiquated international organizations that today ill serve American interests.

These international organizations should advance the interests of member states and their citizens, not perpetuate systems that disproportionately benefit some members over others or serve a narrow elite of self-interested leaders.

Peter Navarro is assistant to the president for trade and manufacturing policy.

The Times is committed to publishing a diversity of letters to the editor. We’d like to hear what you think about this or any of our articles. Here are some tips. And here’s our email: letters@nytimes.com.

Follow The New York Times Opinion section on Facebook, Twitter (@NYTopinion) and Instagram.