system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do Americans put so much faith in their constitution? Why should a 200 year old document be the be all and end all of what is good?

As a Brit, it seems that in the US "unconstitutional" is pretty much the worst thing something can be. Why is this document so sacrosanct and why shouldn't something be a good idea just because it goes against it?
gpt
It was the founding principles of this country, and it has served us well so far.  It's not so sacrosanct that it can't be changed though, this is what the amendment process is all about.  If we find that the constitution has failed us in some way, congress can create an amendment to it to realign it to a changing world.  

It *created* the union - thus it is what created the United States, it was not a law we adopted into an existing country, but rather a law which established that country by its adoption by member states.  It creates congress, it establishes what powers states may *not* have (eg, states cannot mint their own money), it creates the presidency, it creates the judicial system, it makes all states equal, and importantly ***it explicitly allows itself to be amended***.  The creators of this document knew they were not infallible, and that they could not predict what the future holds, so they created a way for the document to evolve with time.

Why do we still use it?  Because it still represents the best form of government we've been able to conceive so far.  If we wanted to eliminate it, we could not claim to be the same country.