The debate between Ken Waltz and Scott Sagan, The Spread of Nuclear Weapons (2nd edition, 2003) is a great teaching tool. Waltz, the academic Grinch of proliferation studies, argues that more proliferation is better than any of the alternatives — as long as the Bomb spreads slowly. Sagan argues that more proliferation increases the likelihood that something will go badly wrong, whether by accident, miscalculation, or from deadly organizational biases. This is a completely unfair fight because Sagan has to be right just once, while Waltz has to be right every time.
Waltz’s views are a reprise of his classic 1981 Adelphi Paper, The Spread of Nuclear Weapons: More May Be Better, which is must reading for Wonks. Here is the unvarnished Waltz:
The gradual spread of nuclear weapons is better than no spread and better than rapid spread.
Possession of nuclear weapons may slow arms races down, rather than speed them up.
In countries where political control is most difficult to maintain, governments are least likely to initiate nuclear-weapon programmes.
Nuclear weapons induce caution, especially in weak states.
Minor nuclear states have even better reasons than major ones to accommodate one another peacefully and to avoid any fighting.
The biggest international dangers come from the strongest states.
The presence of nuclear weapons makes wars less likely.
Even if deterrence should fail, the prospects for rapid de-escalation are good.
In desperate situations, what all parties become most desperate to avoid is the use of strategic nuclear weapons.
It is not likely that nuclear weapons will spread with a speed that exceeds the ability of their new owners to adjust to them. The spread of nuclear weapons is something that we have worried too much about and tried too hard to stop.
Lest arms controllers feel deeply offended, Waltz also throws round-house punches at missile defenses in his debate with Sagan:
National missile defenses pose greater dangers to us and to others than the slow spread of nuclear weapons. The best thing about such defenses is that they won’t work. The worst thing about them is that merely setting development and deployment in motion has damaging effects on us and on them.”
According to [missile defense advocates, would be attackers] are smart enough to calculate the problematic effects of our future defenses, but too dumb to understand the risks of launching attacks that risk their own destruction.
The mere prospect of American missile defense promotes the vertical proliferation of nuclear weapons. It also encourages the horizontal spread of nuclear weapons from one country to another.
Waltz the supreme realist, assumes ever-present rationality… and the absence of Murphy’s Law, except when it comes to missile defenses.