Why buying American can be the practical procurement answer

Why is buying American so often treated as an acceptable military-procurement answer?

Because an established American system is likely to work and be delivered, while creating the domestic industry to replace it can be even more expensive.

Buying American recurs in military procurement even when the imported equipment is not an ideal fit. The system will usually work and is likely to be built and delivered through an existing industrial base. It may bring higher personnel demands, expense, or other operating complications. The alternative of domestic production requires the buyer to create or restore the industry capable of making the equipment, which can cost still more. If national policy does not insist on preserving that sovereign capacity, an expensive purchase can nevertheless be the cheaper practical choice.