Measurement of the “strength” of a military force—the extent to which that force can accomplish missions—requires examination of the environments in which the force operates. Aspects of one environment may facilitate military operations while another may work against them. A favorable operating environment presents the U.S. military with obvious advantages; an unfavorable operating environment may limit the effect of U.S. military power. The capabilities and assets of U.S. allies, the strength of foes, the geopolitical environment of the region, and the availability of forward facilities and logistics infrastructure all factor into whether an operating environment is supportive of U.S. military operations.

When assessing an operating environment, particular attention must be paid to any treaty obligations the United States has with countries in the region. A treaty defense obligation ensures that the legal framework is in place for the U.S. to maintain and operate a military presence in a particular country. Furthermore, a treaty partner usually yields regular training exercises and interoperability as well as political and economic ties.

Additional factors also impact the operating environment, including military capabilities of allies that might be useful to U.S. military operations, the degree to which the U.S. and allied militaries in the region are interoperable (e.g., can use common means of command, communication, and other systems), and whether the U.S. maintains key bilateral alliances with nations in the region. Likewise, nations where the U.S. has already stationed assets or permanent bases, and countries from which the U.S. has launched military operations in the past, may provide needed support to future U.S. military operations. The relationships and knowledge gained through any of these factors would undoubtedly ease future U.S. military operations in a region and contribute greatly to a positive operating environment.

In addition to U.S. defense relations within a region, additional criteria should be considered, including the quality of the local infrastructure, the political stability of the area, whether or not a country is embroiled in any conflicts, and the degree to which a nation is economically free.

Each of these factors contributes to the judgment whether a particular operating environment is favorable or unfavorable toward future U.S. military operations. The operating environment assessment is meant to add critical context to complement the threat environment assessment and U.S. military assessment detailed in subsequent sections of the Index.

This Index will refer to all disputed territories by the name employed by the United States Department of State, and should not be seen as reflecting a position on any of these disputes.