Nuclear weapons and nuclear deterrence have once again invaded the public consciousness. In the past few years, startling facts about these civilization-ending machines have come to light. They were not all mothballed when the Cold War ended. Even poor, isolated countries like North Korea can build them. Terrorists are trying to buy or steal them. They have nearly been detonated by accident many times. American nuclear missile operators were caught gambling, drinking, doing drugs, and cheating on their proficiency tests. President Putin of Russia and some of his generals and political cronies have said they would nuke America if necessary.

Most recently we hear that our nuclear arsenal is outdated, and we need to completely replace it over the next 30 years for a price of about $1 trillion. Ironically, President Obama—who in 2009 dedicated his Administration to work toward the “peace and security of a world without nuclear weapons”—has just submitted a federal budget intended to support such a comprehensive rebuilding, with planned nuclear weapons systems remaining in service until 2080.

Before supporting this plan, the American public, its Congress, and its next president should understand what they are getting into. Just as with personal financial and work/life planning, there is much to consider. Money is only part of the picture. The real objective of investments in nuclear weapons is to support an overall national security strategy that protects us from a range of threats as safely and confidently as possible.

Decisions on modernizing our nuclear arsenal need to be made within this context and with a full appreciation of the resulting costs and risks. Here are a few of them:

First, defense budgets are limited and unlikely to increase above current levels. Tradeoffs therefore need to be made between spending on nuclear weapons and all of the other military priorities like ships, planes, tanks, radars, satellites, missile defenses, foreign bases, counterterrorism, training, and special operations. For example, if we have $200 billion to spend annually on weapons (as opposed to military salaries, health care, and pensions) and spend $30 billion on nuclear forces when $10 billion can buy effective deterrence, we will waste $20 billion annually that could go to other vital defense missions such as fighting ISIS, strengthening our conventional defenses and those of our allies, improved training, cyber-security, and research. If those non-nuclear defense investments are needed to protect us from non-nuclear threats that we are far more likely to face than nuclear attack, short-changing them results in poor national strategy and less security for America.

Russia is the only country in the world that can even remotely threaten our nuclear deterrent. New Start, an agreement reached in 2010 that Russia continues to abide by, keeps our two nuclear arsenals in rough balance, so neither side gains the ability strike first while avoiding a devastating response. This is the essence of nuclear deterrence, and it makes such an attack extremely unlikely. A modernized force of 1,550 deployed nuclear warheads, as permitted by New Start, can be purchased for far less than the $1 trillion 30-year plan envisioned by President Obama’s new fiscal 2017 budget. We certainly can spend that huge amount on nuclear forces at the expense of other military capabilities, but we may also gravely regret it.

Second, planning a full like-for-like replacement of our triad of nuclear forces entails several types of existential and political risk. The most obvious of these is that reliance on nuclear deterrence carries the unavoidable risk of global nuclear catastrophe. Nuclear deterrence can fail, through poor decisions, escalation during a crisis, a series of mechanical and human errors, or malicious acts that lead to inadvertent use. Nuclear weapons are machines that can malfunction with devastating consequences.

Another risk flows from one simple fact: Nuclear weapons and nuclear materials that can be made into weapons can never be perfectly secured from theft or misuse. Terrorists such as ISIS and their ilk are trying to get their hands on a nuke, to blow one up, or to spark a nuclear war between states that would create the atavistic outcome they desire. The more nuclear weapons there are, the greater the risk that terrorists might succeed.

A desire to reduce the risks of nuclear terrorism was one of the reasons that the latest official statement of US nuclear policy, a 2013 report from the Pentagon on US Nuclear Employment Guidance, concluded that America’s nuclear deterrence requirements could be met with a force of 1,100 deployed warheads, nearly one-third less than the 1,550 permitted under New Start. The current plan to modernize and upgrade the entire arsenal of 1,550 deployed warheads, delivery vehicles, and many hundreds of reserve nuclear weapons preserves a greater than necessary risk that terrorists will acquire one.

America’s declared intention to continue upgrading nuclear weapons for 30 years and keep them in service until 2080 or beyond has a political cost, as well. It undermines another objective of US national security strategy, which is to prevent the proliferation of nuclear weapons to other states. The United States and other parties to the 1970 Nuclear Non-Proliferation Treaty have accepted the obligation to accomplish the eventual elimination of their nuclear arsenals. To create the conditions for this to be possible, the United States depends on the cooperation of over 100 nations that have agreed not to acquire nuclear weapons. Many of these states supported the multilateral negotiations with Iran that achieved an agreement to prevent that country from building nuclear weapons. US leadership and credibility for this nonproliferation agenda is weakened by plans to retain nuclear weapons as a central element of America’s national security strategy for another 60 to 75 years.

America also faces a broad range of non-military threats to its security and prosperity in the decades ahead. These include the negative consequences of environmental degradation and climate change, energy security, increasing resource scarcity, financial crises, human migration, pandemics, and the challenge of maintaining a highly skilled and educated citizenry in a competitive global economy. Addressing these threats requires national investments in addition to outlays for our military forces, and tradeoffs must be made within the overall federal budget.

Finally, there is an intangible, psychological cost to nuclear deterrence. Americans born in the 1950s and thereafter have lived their entire lives under the threat of annihilation that President Kennedy called the “nuclear sword of Damocles.” We do not want our children and grandchildren to spend their lives under the same shadow. That is why America should lead the search for more rational and humane ways to achieve security at much lower levels of nuclear weapons. The current plan to spend a trillion dollars over 30 years signals a belief that relying on an international security system based on the willingness of nations to commit mutual suicide is the best we can do. Eventually we must do better.

When the full range of strategic considerations is taken into account the $1 trillion plan for nuclear modernization does not look like the best plan for America’s security. In the years ahead it would be better to acknowledge the full price of nuclear deterrence and make sure that plans for modernizing our nuclear forces at least meet the following criteria:

They deter the range of plausible nuclear threats.

They represent a prudent investment of finite defense resources given the full spectrum of likely security threats, including non-nuclear threats.

They are consistent with current nuclear posture and employment guidance.

They support efforts to prevent nuclear proliferation and nuclear terrorism.

They comply with treaty obligations.

Current plans for like-for-like replacement of all three legs of the nuclear triad, basically replicating today’s force structure, cannot effectively meet several of these criteria. For this reason the public, the Congress, and the next president should consider alternative nuclear modernization plans that offer advantages for meeting deterrence needs and reducing nuclear threats, while making wise, fully-informed decisions for investing finite national security resources.