[HSMW]

2021 US Defense Budget Overview

[Lusitan]

https://www.rand.org/pubs/research_reports/RR2533.html

Understanding the Deterrent Impact of U.S. Overseas Forces

The results of the analysis provide consistent evidence for the deterrent effects of heavy ground forces and air defense capabilities, especially when deployed in the general theater of interest but not necessarily on the front lines of a potential conflict.
The more mobile forces are, the less evidence there is that they deter. This is possibly because mobile forces represent a lesser degree of high-level or long-term U.S. commitment or possibly because measuring their effects is more difficult.
When U.S. forces, particularly light ground forces, are stationed inside the borders of the ally or partner to be defended rather than in nearby states in the broader theater, they are associated with an increased likelihood of militarized disputes.
Analysis shows that, when the United States has surged forces forward in an international crisis, there has been a large decline in the incidence of major clashes or war. Deployments of ground and air forces, in particular, were associated with an extremely low incidence of further escalation.
Countries supported by U.S. crisis deployments appear no more likely to achieve their strategic goals in a crisis than countries that do not enjoy such support. These results suggest that U.S. crisis deployments can help maintain the status quo at reduced risk of war, but they do not readily translate into bargaining leverage or improved long-term positions for partner states.