The treaty on intermediate-range nuclear forces (INF) has sanctified the
“zero option.” It has long been understood that it is easier to verify a
complete ban on a weapon system than it is to verify a numerical limit. A
complete prohibition is easier to verify because a single sighting of a banned
weapon would constitute clear evidence of a violation. Moreover, a complete
ban would eliminate training, testing, and repair activities that could serve as a
cover for clandestine weapon deployments or could support a sudden breakout
from a treaty. Although a total ban may be the best option from the
standpoint of verification, this is not realistic for many weapon system.
In the past, numerical limits could be verified adequately because the
weapon systems in question—missile silos, bombers, and ballistic-missile submarines—
were hard to conceal from national technical means (NTM) of verification
(primarily reconnaissance and electronic intelligence satellites). Unfortunately,
changes in technology and in the strategic environment are giving
rise to new weapons whose deployment will be difficult to verify using current
techniques. Mobile land-based ballistic missiles, for example, are gaining
increased prominence in the strategic forces of both sides, primarily because
they are less vulnerable to preemptive destruction than immobile silo-based
missiles. But mobile missiles are much more difficult to count since they are
designed to move around the countryside and are often hidden from view.
Limits on nuclear cruise missiles would also be difficult to verify using NTM
because they are small and because the conventional- and nuclear-armed versions
are nearly indistinguishable. In addition, the INF Treaty is giving new
impetus to the search for cooperative restrictions on the military confrontation
in Central Europe, where numerical limits have been hard to agree on in
part because of verification difficulties