Is the U.S Bonds market a ponzi scheme?

I've been thinking about it lately, after watching a few videos about Bernie Madoff. He claimed the entire U.S bond market is a ponzi scheme, is this true or not? It makes sense because the U.S government is always in debt – therefore it doesn't have the money to pay back to its investors, just relying on the new money flowing in to pay back maturing bonds. I would love to hear your opinion about it – thank you in advance.