“The point of having nuclear weapons is to deter a war of any kind. They have succeeded in doing so for the past 37 years. To be an effective deterrent a potential aggressor must believe that under certain circumstances such weapons will be used.”

The Tribune (28 March 1986).
1980s

"Reaching Global Zero" (8 March 2011) http://www.huffingtonpost.com/valerie-plame-wilson/nuclear-proliferation_b_832399.html
Context: Without doubt, terrorist groups are trying to buy, build or steal a bomb. Furthermore, there is enough highly-enriched uranium (HEU) in the world to build more than 100,000 weapons, and rogue individuals are selling technology on the black market. If terrorists get hold of HEU, they could not be prevented from smuggling it into a targeted city, building a bomb and exploding it.
To my mind, the only realistic solution to this danger is to lock down all nuclear materials and eliminate all nuclear weapons in all countries: Global Zero. I am now dedicated to achieving this goal as a leader of the Global Zero movement. This movement was launched in December 2008 in Paris by an international group of 100 current and former heads-of-state, national security officials, military commanders and business, civic and faith leaders — and in just two years has grown to 300 leaders and 400,000 citizens worldwide.
The group believes that whatever deterrent value nuclear weapons had in the Cold War is now outweighed by the dangers of proliferation and nuclear terrorism. Our international Global Zero Commission has developed a practical, step-by-step plan to eliminate all nuclear weapons through phased and verified reductions.
To build on the progress made to date, we need a worldwide public movement to make Global Zero an urgent global imperative — and to bring all nuclear weapons countries to the table to negotiate multilateral nuclear arms reductions for the first time in history.

The London Standard (30 September 1986).
1980s

Comments (via satellite) at the Seventh Annual Herzliya Conference in Israel. http://www.herzliyaconference.org/Eng/_Articles/Article.asp?ArticleID=1728&CategoryID=223

"Introduction: Thinkability"
Einstein's Monsters (1987)

Interview (18 December 1997) http://www2.gwu.edu/~nsarchiv/coldwar/interviews/episode-21/turner1.html for CNN : Cold War. Episode 21 : Spies (14 March 1999)
1990s
Context: America and Russia have excessive numbers of nuclear weapons today because we treated nuclear weapons, at the end of World War II, like they were just bigger conventional weapons. If you have tanks, and the other side has more than you, you may be in trouble — or airplanes or ships or whatever. With nuclear weapons, it's not the same: they're too powerful, and at some point you just can't use any more, it's just not meaningful. But what happened was, we had the lead of course, because we invented them. The Russians tried to catch up with us; we tried to stay ahead of the Russians; they tried to catch up with us, and we just had a never-ending race upward. By the mid-Sixties, we realized this, but because of the Cold War mentality, politicians couldn't stand up and say, "I'm willing to have less than the Soviet Union," and so the race continued, but we tried to mitigate it by instituting an arms control process, which at first tried to cap and then later to reduce these numbers. … there's just no way you can actually use them; they become so destructive. I estimate that a couple of hundred nuclear weapons, not just on the center of cities, but on economic positions in the country, will drive a country to the point it will never recover, it will never be the same again. It will survive, but it'll be a totally different country. You don't need thousands to do that. There are only a few hundred cities of any size in even Russia or the United States, like 200, and you just don't need thousands of weapons to demobilize a country.

Speech https://hansard.parliament.uk/commons/1955-03-01/debates/ae81a20b-68e7-42d0-8cbb-d9589f53fc0d/Defence#1896 in the House of Commons (1 March 1955)
Post-war years (1945–1955)

2016 - 2020, Valdai Discussion Club: 15th Plenary Session (18 October 2018)

1961, UN speech
Context: Today, every inhabitant of this planet must contemplate the day when this planet may no longer be habitable. Every man, woman and child lives under a nuclear sword of Damocles, hanging by the slenderest of threads, capable of being cut at any moment by accident, or miscalculation, or by madness. The weapons of war must be abolished before they abolish us.