On the other hand, CRS says, A Defense Department official has been quoted as saying the EPAA mission to be performed by the four BMD-capable Aegis ships to be homeported at Rota would instead require 10 U.S.-homeported BMD-capable Aegis ships to perform.

On that basis, CRS says, it would appear that homeporting four BMD-capable Aegis ships at Rota could reduce demands for BMD-capable Aegis ships by six ships.

“In terms of the balance between demands for BMD-capable Aegis ships and available numbers . . . , the decline in the ramp-up rate in the number of BMD-capable Aegis ships under the proposed fiscal 2013 budget compared to the fiscal 2012 budget might be viewed as offset to a substantial degree, at least in certain years, by the plan to forward-homeport four BMD-capable Aegis ships at Rota,” CRS says.