Many characteristics of SBMD could create uncertainty in the minds of potential adversaries about whether or not they could achieve their aims.
The constant forward presence of SBMD could allow the United States to limit its military footprint on foreign soil and support many military operations simultaneously.
Furthermore, employing SBMD is not contingent on approval from another nation.
Potential adversaries may develop countermeasures in response to the US fielding of an SBMD because the latter would make their capabilities ineffective.
One countermeasure against nonkinetic SBMD capabilities--hardened Missiles--could have a reduced payload due to the added weight of the hardening material and additional fuel needed to reach the required distances.
Space sensors designed to trigger SBMD could also trigger TMD to intercept cruise missiles.
SBMD progressed through various programs, such as GPALS, Brilliant Pebbles, Clementine, and SBL, despite dwindling support from presidential administrations following President Reagan's.
Policy makers need to invest in the development of many different capabilities, including SBMD, to negate missiles in their boost phase and use the information gleaned from these developments to inform decisions.
By funding R&D for SBMD, the United States would ensure the viability of these technologies.