While there is no exact formula that can provide our nation's leaders the answers to these two questions, past history provides a good and prudent guide to the answers we seek even as the current geostrategic conditions in which we find ourselves remind us that the future is indeed hard to predict.
But one answer that makes no sense is once more put forward by two researchers at the CATO Institute. Benjamin Friedman and Christopher Preble (Ending Nuclear Overkill, By Benjamin H. Friedman and Christopher Preble, New York Times, November 13, 2013) argue that our current and planned nuclear deterrent force is more than enough and can be cut significantly by eliminating all our nuclear bombers and land-based missiles and leaving only 12 submarines for our entire nuclear deterrent force.
They further assert that since our deterrent is designed to strike first in a crisis rather than relying upon a on a secure, second-strike retaliatory capability, we should have in our arsenal fewer such weapons. They also argue that at the height of the Cold War, the Soviet Union had no aggressive designs against us so the Triad of forces that was deployed by the United States during that period need not be continued because we were not deterring a real threat. In fact they argue the force we deployed was determined largely by inter-service rivalry, not a genuine threat analysis. And finally, they claim our current and planned deterrent is not really relevant to today's threats such as terrorism and cyber warfare and thus can be safely and dramatically cut.
Let us look at the facts and put aside some fashionable fictions.
For nearly 70 years the US has maintained a nuclear deterrent second to none. We also extended our deterrent over some 31 allies in Europe and Asia. The result? We maintained the peace between the nuclear super powers for nearly 70 years. For centuries before, the great powers averaged between 5-8 great wars every century where more than 1% of the world's population perished each year on average (Former White House Special Assistant to the President, Frank Miller, Address to the Henry Jackson Society, March 20, 2013, House of Commons, London.)
Thus whatever Preble and Friedman think of the current nuclear deterrent structure, it successfully kept the peace for nearly three quarters of a century. One cannot argue with this success.
Another success of the nuclear deterrent posture we maintained throughout the Cold War and beyond was that other nations-such as Germany, Taiwan, and Japan---did not feel compelled to build their own nuclear arsenals as they were safely protected by America's nuclear umbrella. The success of this deterrent was in large part because it consisted of three separate but complimentary missile and bomber systems on land, at sea and in the air. This United States nuclear force structure so complicated an adversary's attack plans that we maintained great crisis stability for, as we noted, over 68 years. That is a perfect record of no wars between the nuclear armed great powers.
This peace was not maintained by accident. As President Kennedy explained after the Cuban missile crisis, the ICBM was "my ace in the hole" (boeing.com/news/frontiers/archive/2008/November.pdf), even though we also deployed at the same time another two legs of our Triad including the Polaris sea-based submarine and the strategic B-52 nuclear bomber.
The revolutionary designed ICBM kept the peace during the Cuban missile crisis and today, some half a century later, continues to be a critical backbone of the US strategic nuclear deterrent. The 450 Minuteman III missiles now deployed in five states is the most cost-effective, cheapest leg of the Triad and very stabilizing as its huge target base cannot be taken out by an adversaries attacking missiles in a cheap or sudden attack.
Having all three capabilities at hand-land-based ICBMs, the sea-based submarines and their missiles and the bombers on alert ready to be airborne-gave the United States unparalleled flexibility during the Cold War to deal with a myriad of crises. The land based missiles gave us assured stability-no one could strike those dispersed silos without prompting a strong retaliatory response by the United States. The submarines could remain at sea for many months, and their current invulnerability from attack under the sea-the Russians cannot find them-gives the US a secure, second-strike retaliatory capability.
On top of which, our nuclear armed bombers can be airborne quickly, safe from attack, and can be used to signal an adversary "we mean business". During the March crisis on the Korean peninsula, for example, our B-2 bombers flew many hours to the Pacific and assured the Republic of Korea that we would not let Pyongyang get reckless.( http://www.nytimes.com/2013/03/29/world/asia/us-begins-stealth-bombing-runs-over-south-korea.html?)
Even more importantly, the three legs provide the US with a hedge against technological surprise and any resulting significant change to the military and political landscape where, for example, our submarines at sea might become vulnerable to attack. If the US relied solely on submarines which Preble and Friedman propose, an American President could be faced with a sudden adverse change in the balance between the US and our enemies, with possible deadly consequences.
To bolster their argument that nuclear weapons are today of less deterrent value, they make two erroneous claims: they assert that our allies' conventional forces alone are more than enough to deter "today's rivals", including rivals with nuclear weapons. And they conclude that the only reason the US built and deployed three legs of the Triad was inter-service rivalry, not geostrategic necessity.
To be clear, they do concede US nuclear deterrence is needed. But they apparently remain very much confused as to how to maintain a deterrent they acknowledge we should keep.
As explained earlier, throughout the past seven decades, our nuclear deterrent prevented the use of nuclear weapons by other nuclear armed powers against American and its allies. But this deterrent has for 68 years also may have stopped the possible use of conventional firepower against central Europe by the Soviet Union, the Republic of Korea by North Korea (the DPRK) and the Republic of Taiwan by the People's Republic of China.
Even though the Cold War is over, American nuclear deterrence remains needed for all these contingencies. This is especially so given the rapid and historically unprecedented current nuclear modernization efforts of Russia, China (PRC) and North Korea (DPRK), among others, (Rachel Oswald, "Experts Divided on Impact to U.S. of Russia, China Nuke Modernization", October 17, 2011, NTI).