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Overseas presence contributes to contingency responsiveness, deterrence, assurance, and security cooperation.

In many cases — but not all — overseas presence enhances contingency responsiveness.

• In-place forces are critical for the initial stage of major contingencies.
• The global en route infrastructure enables reinforcement of in-place forces and broad responsiveness.
• Access to bases from which direct air support can be provided is important.
• Global naval presence contributes to response flexibility.
• Overseas ground forces may not provide an advantage for regional responsiveness when not proximate to the area of conflict.

Overseas forces targeted to specific threats provide deterrence and regional assurance.

• In-place forces signal the ability to thwart quick victories and assure allies of U.S. commitments.
• Regional air and missile defenses protect and assure allies and partners.

Overseas presence enhances security cooperation, which builds U.S. capabilities to work with partners and helps develop their capabilities.

• The marginal cost of security cooperation activity for forces based overseas is low, resulting in higher activity.
• The greatest benefits accrue from working with advanced partners.

Basing has fixed and variable cost elements, with variable costs per person (and overall costs) higher overseas, even when taking host-nation support into account.

• Consolidation by closing a base (anywhere) cuts the fixed cost.
• Realigning forces from overseas to the U.S. reduces costs due to the variable cost difference.

The costs of rotational presence can be more or less than overseas stationing, depending on rotation frequencies, lengths, unit types, and locations.

Some posture changes could be advisable, depending on judgments about national security priorities and the relationships between posture and strategic benefits.

• Further reductions in Europe would reduce costs, but at some penalty in terms of security cooperation and assurance of allies.
• The emerging threat from long-range precision-guided weapons needs to be part of the calculus when adjusting posture in the Asia-Pacific region in the pursuit of deterrence and assurance goals.
• In Asia, another key consideration is the value of having ground forces stationed in the region versus in the United States for flexible contingency response, assurance, and security cooperation with partners across the region.
• In the Persian Gulf, policymakers must weigh the deterrent benefits of presence against the costs and the risks driven by host nations' political sensitivities to U.S. presence.