So you know when you're doubled over in pain and you're wondering, is it your appendix or maybe you ate something funny? Well, when that happens to me, I call my friend Sasha -- Sasha is a doctor -- and I say, "Should I rush to the nearest emergency room in a panic? Or am I OK to relax and just wait it out?" Yes, I am that annoying friend. But in September 2017, friends of mine were suddenly calling me for my professional opinion. And no, I'm not a doctor, but they were asking me questions of life and death. So what was going on in September of 2017? Well, North Korea was suddenly and scarily all over the news. Kim Jong-un had tested missiles potentially capable of hitting major US cities, and President Trump had responded with tweets of "fire and fury." And there was real concern that tensions would escalate to a potential war or even nuclear weapons use. So what my friends were calling and asking was: Should they panic or were the OK to relax? But really, they were asking me a fundamental question: "Am I safe?" While I was reassuring them that, no, they didn't need to worry just yet, the irony of their question dawned on me. What they hadn't really thought about is that we've all been living under a much larger cloud for decades -- potentially a mushroom cloud -- without giving it much thought. Now it's not surprising that friends of mine and many others like them don't know much about nuclear weapons and don't think about them. After all, the end of the Cold War, the United States and Russia, tension abated, we started dismantling nuclear weapons, and they started to become a relic of the past. Generations didn't have to grow up with the specter of nuclear war hanging over their heads. And there other reasons people don't like to think about nuclear weapons. It's scary, overwhelming. I get it. Sometimes I wish I could have chosen a cheerier field to study. (Laughter) Perhaps tax law would have been more uplifting. (Laughter) But in addition to that, people have so many other things to think about in their busy lives, and they'd much prefer to think about something over which they feel they have some semblance of control, and they assume that other people, smarter than they on this topic, are working away to keep us all safe. And then, there are other reasons people don't talk about this, and one is because we, as nuclear experts, use a whole lot of convoluted jargon and terminology to talk about these issues: CVID, ICBM, JCPOA. It's really inaccessible for a lot of people. And, in reality, it actually sometimes I think makes us numb to what we're really talking about here. And what we are really talking about here is the fact that, while we've made dramatic reductions in the number of nuclear weapons since the Cold War, right now, there are almost 15,000 in the world today. 15,000. The United States and Russia have over 90 percent of these nuclear weapons. If you're wondering, these are the countries that have the rest. But they have far fewer, ranging in the sort of 300-ish range and below. Adding to this situation is the fact that we have new technologies that potentially bring us new challenges. Could you imagine, one day, countries like ours and others potentially ceding decisions about a nuclear strike to a robot, based on algorithms? And what data do they use to inform those algorithms? This is pretty terrifying. So adding to this are terrorism potential, cyberattacks, miscalculation, misunderstanding. The list of nuclear nightmares tends to grow longer by the day. And there are a number of former officials, as well as experts, who worry that right now, we're in greater danger than we were in various points in the Cold War. So this is scary. What can we do? Well, thankfully, ["Duck and Cover"] we don't have to rely on the advice from the 1950s. (Laughter) We can take some control, and the way we do that is by starting to ask some fundamental questions about the status quo and whether we are happy with the way it is. We need to begin asking questions of ourselves and of our elected officials, and I'd like to share three with you today. The first one is, "How much nuclear risk are you willing to take or tolerate?" Right now, nuclear policy depends on deterrence theory. Developed in the 1950s, the idea is that one country's nuclear weapons prevents another country from using theirs. So you nuke me, I nuke you, and we both lose. So in a way, there's a stalemate. No one uses their weapons, and we're all safe. But this theory has real questions. There are experts who challenge this theory and wonder: Does it really work this way in practice? It certainly doesn't allow for mistakes or miscalculations. Now, I don't know about you, but I feel pretty uncomfortable gambling my future survival, yours, and our future generations', on a theory that is questionable and doesn't allow any room for a mistake. It makes me even more uncomfortable to be threatening the evaporation of millions of people on the other side of the Earth. Surely we can do better for ourselves, drawing on our ingenuity to solve complex problems, as we have in the past. After all, this is a man-made, human-made -- I shouldn't say "man," because women were involved -- a human-made problem. We have human solutions that should be possible. So, next question: "Who do you think should make nuclear decisions?" Right now, in this democracy, in the United States, one person gets to decide whether or not to launch a nuclear strike. They don't have to consult anybody. So that's the president. He or she can decide -- within a very limited amount of time, under great pressure, potentially, depending on the scenario, maybe based on a miscalculation or a misunderstanding -- they can decide the fate of millions of lives: yours, mine, our community's. And they can do this and launch a nuclear strike, potentially setting in motion the annihilation of the human race. Wow. This doesn't have to be our reality, though, and in fact, in a number of other countries that have nuclear weapons, it's not, including countries that are not democracies. We created this system. We can change it. And there's actually a movement underway to do so. So this leads me to my third question: "What do your elected officials know about nuclear weapons, and what types of decisions are they likely to take on your behalf?" Well, Congress has a very important role to play in oversight of and interrogating US nuclear weapons policy. They can decide what to fund, what not to fund, and they represent you. Now unfortunately, since the end of the Cold War, we've seen a real decline in the level of understanding, on Capitol Hill, about these issues. While we are starting to see some terrific new champions emerge, the reality is that the general lack of awareness is highly concerning, given that these people need to make critically important decisions. To make matters worse, the political partisanship that currently grips Washington also affects this issue. This wasn't always the case, though. At the end of the Cold War, members from both sides of the aisle had a really good understanding about the nuclear challenges we were facing and worked together on cooperative programs. They recognized that nuclear risk reduction was far too important to allow it to succumb to political partisanship. They created programs such as the Nunn-Lugar Cooperative Threat Reduction Program, which sought to lock down and eliminate vulnerable nuclear material in the former Soviet Union. So we need to return to this era of bipartisanship, mutual problem-solving that's based on understanding and awareness about the challenges we face and the real nuclear dangers. And that's where you come in. Public pressure is important. Leaders need a constituent base to act. So create that constituent base, by asking them some simple questions. Ask them, "What do you know about nuclear weapons?" "Do you have a nuclear expert on your staff? Or, if not, do you know somebody you could refer to if you need to make an important decision?" Start to find out what they believe and whether it aligns with your own views and values. Ask them, "How would you choose to spend US national treasure? On a new nuclear arms race or another national security priority, such as cybersecurity or climate change?" Ask them, "Are you willing to put aside partisanship to address this existential threat that affects my survival and your constituents' survival?" Now, people will tell you nuclear policy is far too difficult to understand and complexed and nuanced for the general public to understand, let alone debate. After all, this is "national security." There needs to be secrets. Don't let that put you off. We debate all sorts of issues that are critically important to our lives -- why should nuclear weapons be any different? We debate health care, education, the environment. Surely congressional oversight, civic participation that are such hallmarks of US democracy, surely they apply here. After all, these are cases of life and death that we're talking about. And we won't all agree, but whether or not you believe nuclear weapons keep us safe or that nuclear weapons are a liability, I urge you to put aside partisan, ideological issues and listen to each other. So I'll tell you now what I didn't have the guts to tell my friends at the time. No, you're not safe -- not just because of North Korea. But there is something you can do about it. Demand that your elected representatives can give you answers to your questions, and answers that you can live with and that billions of others can live with too. And if they can't, stay on them until they can. And if that doesn't work, find others, who are able to represent your views. Because by doing so, we can begin to change the answer to the question "Am I safe?" (Applause)