How has it demonstrably failed? America is the wealthiest, most successful, most powerful country in human history.

We're definitely the wealthiest. Our power is slipping thanks to awful foreign policy, and success is limited. We've been successful in generating massive amounts of wealth, but our standard of living isn't great compared with many other countries, and despite our wealth, our middle class is shrinking, and we have more homeless than ever, many of whom are veterans. And that's not even going into how a huge amount of our wealth can be directly traced to extremely exploitative attitudes and actions concerning other countries.

There's a lot to be proud of but there's also a lot to be ashamed of.