Yes they are very failed, my opinion why:
First and 1 of the most important:
They have the biggest debt of all country's
They Still spend most money on The army and war
Guns are allowed
Politicians are corrupt
They try to scare the people all over the world with terrorism.
1. They have the biggest debt because they have the largest GDP. They use debt as an instrument to fund growth.
2. Guns being legal is not in itself an evil, it's people being irresponsible with guns that are the issue.
3. All politicians are corrupt in some form or fashion. Look at any country that allows campaign donations.
4. Terrorism isn't America's fault (entirely), though their interventions do seem to provoke it.