Some quick Googling tells me that the fifth amendment was ratified in 1791, 74 years before slavery was abolished. So apparently the US didn't really take that one seriously from the start.
More recently, I recall the case of David Hicks, an Australian citizen. He was declared an "enemy combatant", detained without charge and tortured in Guantanamo bay until he signed a confession to a law which did not exist at the time he was detained.
You should read more here: https://en.wikipedia.org/wiki/David_Hicks#Guantanamo_Bay
Regardless of the stupidity and provocativeness of Hicks' actions, he is a citizen of a nation that is supposedly a US ally, and one would think a person under the US constitution, but he received no protection. The US abused him while the AU government did nothing.
The US government ignores it's own constitution whenever it finds it inconvenient, and any objections are arm-waved away as being legal by the findings of a secret court no US citizen is allowed to know the inner workings of.
It doesn't matter what's written on some crusty paper in a museum somewhere if no one actually abides by it. The US constitution is dead, and I would certainly not trust my liberty to the tender mercies of those who have nailed it's corpse to their standard.