Editor's Note: (Kingston Reif is the Director for Disarmament and Threat Reduction Policy at the Arms Control Association. You can follow him on Twitter at @KingstonAReif. The opinions expressed in this commentary are his.)
(CNN) The possibility of Donald Trump winning the presidential election this November has renewed media and public interest in one of the most important responsibilities of the president: commanding America's massive nuclear arsenal and averting nuclear war.
Yet what has been lost in the angst that Mr. Trump might soon have the authority to launch nuclear weapons is the equally unnerving reality that the U.S. nuclear posture is already unnecessarily dangerous and redundant. Neither Trump nor Hillary Clinton have explained how they would seek to put U.S. doctrine on a safer footing and reduce global nuclear weapons risks.
Last week, much to the concern of the Washington national security community, it was reported that Trump allegedly asked an anonymous foreign-policy expert multiple times why, if the United States has nuclear weapons, it couldn't use them.
Trump denies this exchange took place. But he raised a similar question in March. And while Trump says he would be the last to use nuclear weapons, he has repeatedly not ruled out using nuclear weapons against the Islamic State or in Europe.
What kind of destructive power would a President Trump have at his fingertips?
At any moment, there are roughly 900 U.S. nuclear warheads -- all of which are far more powerful than the weapons that destroyed Hiroshima and Nagasaki in 1945 -- that can be launched within minutes of an order by the president. (The United States is estimated to possess a total arsenal of approximately 7,100 nuclear warheads.)
The president has the sole authority to launch nuclear weapons, and in some scenarios would only have minutes to confirm an incoming nuclear attack and give the order to strike. To date, every president has retained the option to use nuclear weapons first -- even if the United States or an ally has not suffered a nuclear attack.
Most Americans are learning these mind-boggling facts for the first time. Put simply, the fate of tens of millions depends on the good judgment and stability of a single person.
All of which makes Trump's erratic behavior and loose talk on nuclear weapons deeply concerning. Responsible leaders understand that the use of nuclear weapons would be a terrible and likely catastrophic game changer. There can be no winners in a nuclear war.
Yet the reality is that U.S. nuclear strategy is based on a Faustian bargain: In the name of deterring nuclear attack, the United States sustains thousands of nuclear warheads; a diverse array of sea-, land-, and air-based delivery systems; and detailed plans to use the weapons -- including the capability to use them first and at a moment's notice.
The prospect of a President Trump forces us to ask if the threat of mutual annihilation is necessary or sustainable in perpetuity. Human beings, after all, are fallible. False warnings of nuclear attack have occurred on numerous occasions in the past. The risk of miscalculation in a crisis is real.
The odds of a catastrophic accident or uncontrolled nuclear escalation would be greatly reduced if the United States built its nuclear strategy more heavily on retaliation instead of prompt launch and the option for first use. This would entail eliminating any requirement to promptly launch a massive nuclear strike and a declaration that the president would only use nuclear weapons in response to a nuclear attack against the United States or its allies. The costs and risks of the current approach are significant, while the benefits are slim to none.
The urgent need for a national conversation on the underpinnings of U.S. nuclear policy is heightened by the growing risks of global nuclear weapons competition.
Relations between the United States and Russia, which together possess more than 90 percent of the roughly 15,500 nuclear weapons on the planet, have sunk to their lowest point since the end of the Cold War. Progress on further bilateral nuclear cuts is on hold.
As former U.S. Secretary of Defense William J. Perry warned last month: "We're sleepwalking into a new Cold War. There's hardly any debate about it."
In fact, nearly every one of the world's nine nuclear-armed states is engaged in a costly, multi-decade effort to modernize and improve the capability of their nuclear weapons and delivery systems.
The United States alone is projected to spend $1 trillion over the next 30 years to sustain and rebuild its nuclear arsenal -- despite concerns the plans are unsustainable and would leave in place force levels that exceed what President Barack Obama has said is required for deterrence.
And while the international community has put the brakes on Iran's nuclear program, an unconstrained North Korea continues to test and perfect nuclear explosive devices and the ballistic missiles to carry them.
How would the candidates for president address these problems?
Apart from promising to tear up the Iran nuclear agreement and wondering if Japan and South Korea should be acquiring their own nuclear weapons (both of which would have devastating consequences for U.S. security), Trump has said virtually nothing about his plans on nuclear weapons issues.
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Clinton says she will "vigorously enforce" the 2015 Iran nuclear agreement and intensify efforts to safeguard nuclear materials. But she has said little more.
Against this backdrop, President Obama is reviewing a number of proposals to sensibly adjust outdated U.S. nuclear thinking and head off the possibility of a new nuclear arms race, including a declaration that the United States will not be the first to use nuclear weapons and adjustments to the current, costly plan for nuclear weapons modernization. What he ultimately decides to bequeath to his successor remains to be seen.
Regardless, the American public deserves to know what the candidates to be the next president propose to do to reduce nuclear dangers facing the United States and the world, including those which could arise from our own obsolete policies.