Should the US modernize and expand its nuclear arsenal?

The Debate
Brad Roberts, professor, Georgetown, and former nuclear policy advisor to Obama, 2016, The Case for U.S. Nuclear Weapons in the 21st Century, Kindle edition, page number at end of card.
THE UNITED STATES IS ENTERING A PERIOD OF RENEWED debate about nuclear deterrence. That debate will address the most fundamental question: Are U.S. nuclear weapons merely Cold War relics that belong in “the dustbin of history” along with communism and the Soviet Union, or do they make an important and irreplaceable contribution to the national security of the United States? This debate will be driven by three key factors. The first is the reassessment of U.S. defense strategy after fifteen years of war in Afghanistan and Iraq. A number of questions come into play. Is a shift away from counter-terrorism and counter-insurgency possible for U.S. military planners? Is the intended “rebalance” of security strategy toward Asia possible given widespread instability in the Middle East and Russian assertiveness in Europe? Is limited war with China and/ or Russia a serious possibility? Is war with North Korea likely; if so, how might it exploit its new military capabilities to try to secure its interests? Will Iran “go nuclear” and with what implications for U.S. military strategies? What can the United States do to constructively shape developments in the Middle East while insulating itself and its allies and partners from the effects of deep and sustained conflict there? Answers to each of these questions have important implications for U.S. nuclear policy and posture. Developments in the security environment that call into question some of the premises   of U.S. policy since the end of the Cold War also play a role in driving renewed debate. The profound changes in Russia’s foreign policy in 2014 have raised fundamental questions about the future role of nuclear weapons in Europe and in U.S.– Russian relations more generally. North Korea’s progress in developing weapons capable of reaching the United States highlights an emerging major challenge to U.S. security strategy. China is making significant progress in deploying the key elements of a secure nuclear retaliatory force. Some U.S. allies in Europe, Asia, and the Middle East feel pressured by these developments and are seeking new forms of assurance that the U.S. security commitment to them will remain credible over the long term. New premises might well drive U.S. nuclear policy in new directions. In addition, policy makers in Washington need to decide whether and how much to invest in keeping U.S. nuclear forces viable. For the last twenty-five years or so, the United States has spent only the money needed to operate and maintain standing nuclear forces. It has not had to modernize or replace them. Over the next twenty-five years or so, the entire remaining triad of delivery systems and inventory of weapons will have to be modernized or replaced in some way. These will be inherently contentious decisions, not least because they come at a time of budget austerity and in competition with the need to renew nonnuclear forces after more than a decade of war in Iraq and Afghanistan. But the United States is ill prepared for this debate. Most of the stakeholders in the debate about U.S. nuclear deterrence policy and posture made up their minds a long time ago about the big questions. They generally fall into two camps with different core beliefs. One camp recoils from the horror of nuclear war, sees the risks of nuclear terrorism as   high, seeks the abolition of nuclear weapons, and advocates strongly for steps by the nuclear weapons states toward that end. It places a particular onus on the United States to take additional substantial steps at this time to reduce its reliance on nuclear weapons and otherwise lead by example. It makes a passionate case against nuclear weapons and for disarmament. The other camp accepts nuclear weapons as necessary and useful, sees risks from both states and nonstate actors, and advocates for retention of U.S. nuclear forces sufficient to U.S. military and political purposes. It rejects the notion that abolition would make the world a safer place. It resists continued steps to marginalize nuclear weapons in U.S. security strategy. Its case for nuclear weapons is pragmatic but not passionate in the way of the disarmers. These two camps do not debate each other so much as they pursue competing agendas. Though there are examples of respectful discourse between them, adherents of each camp are generally contemptuous of the views of the other. Given the long-standing and deep divisions between these two camps, agreement on policy is rare. One practical result of this divergence has been gridlock in Congress, which has found it difficult to produce decisions in support of any particular nuclear policies. Looking for a way out of this gridlock, in 2007 Congress created a commission, with an equal mix of Democrats and Republicans, and essentially asked it two simple questions. Is there any basis for a renewal of bipartisanship sufficient to sustain U.S. nuclear policy over the longer term? If so, what is it? Despite strong differences of opinion on many matters, members of the Strategic Posture Commission converged on a hopeful note. Policy continuity is possible, they argued, on the basis of a balanced approach that combines   political efforts to reduce and ultimately eliminate threats with military efforts to deter existing threats. Seven years later, a third camp has not coalesced around this balanced approach. This is so despite the fact that the Obama administration embraced this approach and used it as a guide in developing and implementing its nuclear policy. Adherents of the other two camps sometimes praise the virtues of the balanced approach, but rarely are such words followed by deeds of advocacy in support of policy initiatives that depart from the canon of their camp. Roberts, Brad. The Case for U.S. Nuclear Weapons in the 21st Century (p. 3). Stanford University Press. Kindle Edition.
Status QUo
Air Force hires two firms to start developing America’s next generation ICBM.
Donald Trump has no clue about nukes.  Although this concludes as a Con article, it is a good review of all of the different nuclear weapons the US has in its arsenal.
If Trump can figure out how to pay for $1 trillion in new nukes, God bless him. The article doesn’t take a position on whether modernization is good or bad, but it does identify the ambiguity in what trump said and the difficulty in finding $1 trillion to modernize the nuclear force without cannabilizing other weapons.
Trump challenges the world order. The article discusses the the indeterminacy of Trump’s nuclear modernization/potential expansion tweet and the problem of potentially making an announcement makes for US allies and the nonproliferation regime. I don’t think the article has any cards, but it is a good read to understand the background issues related to the tweet.
Could Trump’s tweets spark a nuclear arms race?
Is Trump serious about nukes? 
The problem with America’s nuclear weapons: They’re really old.
Nuclear force modernization costs much less than you would think 
Why America must modernize its nuclear bombers, submarines, and missiles 
Towards a more flexible NATO nuclear posture. This argues the US needs needs new nuclear weapons and needs to work with NATO on a deployment plan to deter Russia in Europe.
Trump said the US should expand nuclear weapons. He’s right . This makes a general case that we need to expand our nuclear arsenal to deter China, North Korea, and Russia.
Trump may be about to delay nuclear modernization plan. This article makes a general case that nuclear modernization shouldn’t be delayed.
The nuclear threat environment facing the Trump administration. This article relays the various nuclear threats and argues for modernization.
Trump administration’s nuclear policy: First steps . This article suggests steps Trump should take to modernize the arsenal.
Countering Russia’s strategy for regional coercion and war.  This paper argues that we need to strengthen nuclear deterrence to prevent Russian coercion in Europe.
Regional nuclear dynamics.  Testimony from various qualified sources argues that expanded nuclear deterrence is needed to support regional deterrence, particular of emerging nuclear powers.
America’s nuclear deterrence holiday.  This brief article contends we need to strengthen nuclear deterrence to counter Russia and China.
Trump tweets, liberals go nuclear.  This article argues that the liberal reaction to Trump’s tweet is an overreaction and that we need to modernize our nuclear forces.
Trump, nuclear realist, can correct Obama’s idealistic ways.
The Case for Nuclear Weapons in the 21st Century (book).  The title of this 2016 book says it all.
Nuclear weapons in the 21st Century.  This blog post is critical of the book above.
Timeline to catastrophe . This article argues nuclear modernization risks nuclear war.
The ongoing modernization of the United States’ nuclear arsenal. This article has some strongly worded evidence that impacts nuclear weapons modernization.
UNSC Test Ban Initiative: Reinforcing existing norms . This article argues the US should restrain its nuclear modernization in order to support non-proliferation norms.
Trump tweet could signal dangerous shift. This post argues that current modernization levels are sufficient and that developing new weapons will risk a war.
The Donald and nukes, again.  This post argues that nuclear weapons expansion will undermine the new START agreement with Russia, risking disruptions in arms control and reciprocal notifications.
Nuclear orthodoxy after Trump (gated). This article argues that nuclear deterrence only requires a limited number of nuclear weapons and that we need to reduce our nuclear weapons because of thin-skinned President Trump.
Trump threatens to upend US nuclear weapons policy 
A competitive strategies approach to defining the US nuclear posture.
Obama already spent $20 billion/year to upgrade US nukes
Related — Accidents
Nuclear war by mistake
Websites — Con
Arms Control Association
Arms Control Today (a publication of the Arms Control Association)
Center for Arms Control and Non-Proliferation
Project Plougshares
Stimson Center