Nuclear weapons came to be in a world that was vastly different from our world today. This was a world in which most were intimately familiar with all-out war, a world that saw the decline of an old empire and the emergence of a new American one — a world in which international institutions that still govern our world today were created to bring coherency to chaos. Nuclear war was the greatest security challenge and threat to human safety then, and many believe that nuclear proliferation and the possibility of a nuclear attack poses the greatest threat today.

If only peripherally, most people living today have lived in a world in which the threat of nuclear weapons continues to pose a significant threat. In fact, this threat or security challenge is one of the few things that has remained constant in the world as it was then and the world as it is now. In old ways and in some new, nuclear proliferation moves us closer and closer to irreparable harm. While the United States and Russia hold 95 percent of the world’s nuclear-weapon stockpile, we no longer fear a nuclear attack from Russia nor do the Russians fear an attack from us. To a certain extent both the United States and Russia (formerly the Soviet Union) were deterred from attacking the other with a nuclear missile because it would lead to the mutual destruction of both. These two Cold War notions of deterrence and mutual assured destruction panned out.

But while we escaped nuclear war with Russia, the proliferation of nuclear weapons to other countries makes the possibility of one country attacking another with a nuclear weapon real. A terrorist organization acquiring a nuclear weapon, even a crude one, would be an absolute game changer. And the ambition of some countries to obtain a nuclear weapon could destabilize already volatile regions and engulf the world in conflict. Think India and Pakistan. Think Iran and North Korea. Think about the numerous weak and fragile states that exist in our own hemisphere where a terrorist organization could effectively launch a nuclear missile onto American soil.

Now is a time like any other to elevate nuclear proliferation as a critical security and survival issue for the entire international community to deal with. And the reason I write about this topic is because we are seeing just that. President Obama at the end of his most recent trip abroad is going to come back to the United States with a significant agreement with Russia to decrease the number of nuclear arms. Obama’s speech in Prague earlier this year calling for “a world without nuclear weapons” signaled that nuclear proliferation would be a top priority of his administration. Although North Korea’s actions are extremely troublesome, they have caused proportionally just about the same amount of alarm and concern among other countries.

We are seeing tremendous movement on this issue. Yet what we don’t see is a public as engaged or that cares significantly enough about nuclear nonproliferation to possibly make more progress. Even for those who are the most politically active, when’s the last time you and your friends got into a discussion about nuclear proliferation?

The threat and the challenge that nuclear proliferation poses is one of the most serious challenges we face today. And to further reduce our nuclear stockpiles and persuade others to give up theirs and relinquish their pursuit of nuclear weapons will be difficult for many reasons. But now, if the public takes this issue seriously, we might be able to see the biggest change of all between the world we live in and the world that was not so long ago, a world without nuclear weapons.