US defense spending is nothing more than transferring a metric ton of tax payer money to private defense contractors… who in turn reallocate a very small fraction of this money back into the economy via jobs (which are increasingly going to prison inmates). They then use these weapons to go overseas and plunder another country for their resources.
All because they fill the coffers of politicians to help them get elected, and then pay them as lobbyists to ensure the cycle continues no matter the candidate.
That’s defense spending in a nutshell. No politician believes the pretense of needing to spend that much to “keep America safe.”
Hell, an arsenal of a few nukes is all we really need to ensure security from any military invasion.