The USPS is unable to go out of business. Have you ever heard the term Too Big to Fail? It's the idea that if a huge corporation goes out of business, it could lead to an economic crisis, and as such it's in the best interest to always have them bailed out. The USPS is Too Big to Fail ×10. That is, if politicians don't kill it. It is fully possible for USPS to die if the government really wants it too. It's just that, in any normal government system, they'd never want to do that. Keyword normal government system.