Why would it be inefficient for the government to charge a price for consuming a public good such as national defence?

Question

Quizplus · Accepted Answer

Public goods like national defence are non-excludable and non-rivalrous, meaning the marginal cost of providing them to an additional person is zero. Charging a price would be inefficient as it would exclude some individuals without reducing the cost of provision.

Why Would It Be Inefficient for the Government to Charge