How should forces be allocated among the four threats given today's budget pressures? Any calculation must involve balancing three factors: the likelihood of having to face the threat, the consequences of failing to handle the threat, and the efficacy of the military instruments against the threat.

The time dimension is also critical. There is no a priori reason to suggest that the threat from bullies is likely to grow. Similarly despite the existence of regional trends (e.g., in sub-Saharan Africa), on a global basis it is harder to discern a trend in favor of more failed states.

Although the incidence of terrorist attacks may not rise, potentially new weapons (e.g., nuclear materials, engineered germs, and computer viruses) may make such incidents more deadly. A peer threat, however, requires a hedge; the United States has none today and almost certainly will not have one for another ten to twenty years but afterwards is anyone's guess.

These factors suggest maintaining a strong (but not necessarily large) capability against terrorism and chaos, seeking an appropriate level of capability against bullies and focussing long-term resources against threats from peers (whether direct or via proxy).