Many Americans are concerned that the belligerent and impulsive behavior of President Trump could lead us into war and, in a worst-case scenario, into nuclear war. The President can independently order the launch of nuclear weapons at any time and for any reason. Furthermore, Trump’s announced intention to withdraw from the Intermediate-Range Nuclear Forces Treaty (which has been in force for over 30 years) and to spend $1.7 trillion to update the U.S.’s new nuclear arsenal increase the likelihood of nuclear war.
With these and other factors in mind, the Bulletin of the Atomic Scientists has moved its Doomsday Clock to 2 minutes from midnight (i.e., doomsday). The clock had been at 17 minutes from midnight in 1991 but has been moving closer since then and has moved from 3 minutes away in 2016 to 2 minutes today.
Any nuclear war would have catastrophic consequences for human beings and our planet. Detonation of one-tenth of the 15,000 nuclear weapons that exist (with all but about 1,000 of them in the hands of the U.S. and Russia) would almost certainly kill all humans on the planet via the huge radioactive cloud that would circle the Earth and rain down everywhere.
Even the detonation of a single nuclear weapon would, of course, be locally devastating. Today’s nuclear weapons are up to 100 times more powerful than the two bombs the U.S. dropped on Japan at the end of World War II, each of which destroyed an entire city and killed roughly 100,000 people.
The U.S. should reduce the likelihood of accidentally launching a nuclear weapon, many of which are still on a quick-launch protocol that dates from the Cold War with the Soviet Union. We could change our policies on the initial use of nuclear weapons, re-evaluate missile defense, and strengthen diplomacy. We could also do more to reduce the possible use of a nuclear weapon by terrorists or other countries around the world. The Union of Concerned Scientists has excellent information on all of this on their website.
The most encouraging news on the nuclear weapons front is the Treaty on the Prohibition of Nuclear Weapons (TPNW), which is now in the ratification process around the world. On July 7, 2017, a United Nations conference adopted this Treaty by a vote of 122 countries in favor, one opposed, and one abstention. The conference met for over 40 days in 2017 with all U.N. member countries, along with non-governmental organizations, encouraged to participate.
The Treaty will go into effect 90 days after the 50th country ratifies it. The Treaty includes comprehensive prohibitions on developing, producing, testing, possessing, or threatening to use nuclear weapons.  The Treaty’s introduction states that given “the catastrophic humanitarian consequences … from any use of nuclear weapons, … the only way to guarantee … [they] are never used again” is to “eliminate such weapons.” It notes that “any use of nuclear weapons would be contrary to the rules of international law … abhorrent to the principles of humanity and the dictates of public conscience. … Concerned by the slow pace of disarmament … and the waste of economic and human resources on … the production, maintenance and modernization of nuclear weapons” the conference participants agreed that the elimination of nuclear weapons was necessary and appropriate. 
The International Campaign to Abolish Nuclear Weapons (ICAN), a coalition of over 500 organizations in over 100 countries and the winner of the 2017 Nobel Peace Prize, is working to get the Treaty ratified. So far, 69 countries have signed it and 19 have ratified it. Once 50 countries ratify it, nuclear weapons will be banned under international law. 
The U.S. has not ratified the Treaty, but California, the U.S. Conference of Mayors, and several cities and towns, including Los Angeles and Baltimore, have endorsed it. Raising the issue of unnecessary, expensive, and dangerous nuclear weapons may serve as a vehicle to more broadly address the U.S.’s militarism, which is harmful geopolitically and economically.
I urge you to contact your local, state, and national elected officials and to ask them to endorse the Treaty on the Prohibition of Nuclear Weapons. These weapons serve no rational purpose and their existence is an existential threat to humankind. The costs and dangers of simply having and maintaining them, of terrorists capturing and using a nuclear weapon, and of working with and disposing of the radioactive material involved are not justifiable. A world free of nuclear weapons would be a safer and saner planet to live on.
 United Nations Office for Disarmament Affairs, Retrieved from the Internet on 1/5/19, “Treaty on the prohibition of nuclear weapons” (https://www.un.org/disarmament/wmd/nuclear/tpnw/)
 United Nations Conference to Negotiate a Legally Binding Instrument to Prohibit Nuclear Weapons, Leading Towards their Total Elimination, 7/7/2017, “Treaty on the Prohibition of Nuclear Weapons” (https://www.un.org/disarmament/tpnw/)
 Fihn, B., 11/8/18, “The fate of the earth depends on women,” The Nation (https://www.thenation.com/article/nuclear-prohibition-beatrice-fihn/)