The United States controls the most lethal nuclear arsenal on the planet. We have nearly 7,200 nuclear warheads, and when combined with Russia’s total, our two countries possess more than 90 percent of the world’s nuclear weapons. We could literally destroy the world many times over.

Yet with election day just over four weeks away, the American people still know very little about Donald Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE’s views of nuclear weapons.

ADVERTISEMENT

Americans deserve to know what their next Commander in Chief thinks about these weapons of war. This Sunday, ABC News’ Martha Raddatz, CNN’s Anderson Cooper and the attendees at the second presidential debate in St. Louis have a unique opportunity to rectify this failure.

At the debate, Trump must be asked two crucial questions about nuclear weapons: first, when would he use them? And second, how would he prevent their global proliferation?

Why does this matter? Unlike any other issue, the president has total control of the nuclear codes. No other American — not a general, not a cabinet member, not a Supreme Court Justice — can stop him or her from using them. There are no real checks and balances when it comes to using the nuclear arsenal.

Yet the statements Trump has made about nuclear weapons during this campaign are simply terrifying. When questioned about their use, Trump has meandered between protestations about how he would never use them to refusing to answer the question.

However, he has dropped certain confusing hints about his views. He’s suggested that he may encourage countries like Japan, South Korea and Saudi Arabia to develop their own nuclear weapons. And MSNBC’s Joe Scarborough has even reported that Trump asked during one national security briefing: “If we have them [nuclear weapons], why can’t we use them?” — sending a collective shiver up the spines of everyone who fears nuclear annihilation.

In a world with multiple nuclear weapons states, Trump’s erratic rhetoric fuels the type of uncertainty that leads to major miscalculation — and potential disaster. Take for example the Cuban Missile Crisis. At that time, President Kennedy didn’t know Soviet Premier Khrushchev’s intentions, and it led to near catastrophe. Only when the two leaders had direct communications about their intentions — and their desire to not have a nuclear war — did cooler heads prevail and was war averted.

Leaders must be clear and credible, not intemperate and unpredictable, to avoid a calamitous miscalculation.

If Trump’s plan is to leave our nuclear state adversaries guessing, then it’s more likely that he’ll scare them into taking preemptive nuclear action against us. And if Trump believes that he would use nuclear weapons against non-nuclear state actors — such as the Islamic State, which he has hinted about — then he would be using them against millions of innocent civilians without either justification or proportionality, turning the United States into a nuclear aggressor.

Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE has taken a starkly different approach. As Secretary of State, she played an important role in preventing the spread of nuclear weapons around the world. As a presidential candidate, Clinton has called for a new Nuclear Posture Review to ensure that our nuclear arsenal is prepared to meet present and future threats. She is thinking deeply about ways to better manage our nuclear arsenal while keeping the American people secure.

This is exactly the type of leadership we need and that Clinton provides. What we don’t need are leaders, such as Trump, who view nuclear proliferation as either inevitable or beneficial to our national security. It is not.

For the past half century, ever since President Kennedy’s administration, the goal of American nuclear weapons policy has been to prevent their spread while avoiding ever having to use them. And we’ve had successes in the past half dozen years on President Obama’s watch. We’ve concluded a diplomatic agreement to prevent a new nuclear state in Iran. We’ve concluded an agreement with Russia to slash both our countries’ nuclear stockpiles. And we’ve pressed the international community to adopt a nuclear test ban treaty. Hillary Clinton played a central role in all of these successes.

The moderators at the next presidential debate must therefore put these issues front and center. We need a Commander in Chief who not only has the temperament to handle the challenges of the nuclear arsenal, but also one who understands what it’s all about.

Let’s get this right on Sunday. Because once you drop the bomb, you can’t take it back.

Rubin is a former Deputy Assistant Secretary of Legislative Affairs for the U.S. Department of State. He was responsible for building support in the House of Representatives for the nuclear agreement with Iran. Rubin has also worked with the Ploughshares Fund, an organization dedicated to preventing the spread of nuclear weapons.

The views of Contributors are their own and are not the views of The Hill