After months of “fire and fury,” a summit, “beautiful” love letters and a promise the North Korean threat was resolved, the latest nuclear weapons negotiation between the United States and North Korea failed. This isn’t surprising.

We haven’t seen a U.S.-North Korea agreement because nuclear policy is hard. Negotiating takes time, innovation, expertise and having the best minds involved in the process — including women.

But women were notably not represented at the last Trump-Kim summit. At the negotiating table were nine men; the only woman was an American translator. Translating has long been considered a “feminine” job in international delegations. This work powered the United States’ rise over the 20th century, yet it reflects how women have been directed to support male-designed policy rather than contribute to its creation. As our research into women’s history in this field since the 1970s shows, for decades, women have been sidelined in nuclear policymaking. That makes our world less safe.

Exclusion in the national security world means ignoring those who may have more experience and knowledge about a region or population, the ability to foresee obstacles others are blind to and more potentially effective and innovative solutions. In the nuclear field, where the stakes are life and death on a massive scale, this exclusion is costly.

Although they may not have been prominent at the Trump-Kim negotiation, women have been integral to the nuclear diplomacy field from the beginning. Female scientists in the Manhattan Project held a range of positions, including physicists, chemists and phlebotomists, working with male researchers to study plutonium and troubleshoot nuclear reactors. As the nuclear arsenal expanded, so did the number of women working as translators, counsels and senior policy and national security advisers. Beginning in the 1970s, women served as under, assistant and deputy secretaries, and starting in 1993, as Cabinet-level secretaries in the State, Defense and Energy departments.