Since it is the sole charge of the SCOTUS to uphold, interpret and define the Constitution of the United States, what plausible reason could there be to "consider" or "consult", as you so deftly put it, laws and/or statutes of foreign entities?
This nation and it's laws have been in existence for well over 200 years. We are the world's foremost repository of constitutional law for representative republican democracies. Additionally, we are the world's most incarcerated nation.
Given that, why would we reference these other nations for a definition of what is "cruel and unusual"?
The very fact that the Court felt the need to do this dramatically points up it's current shortcomings.
Yours is a difference without distinction.
CA....
When defining "cruel and unusual" it is appropriate to look at what is "usual" hence looking at foreign laws is appropriate.
And if you believe justices never considered or consulted foreign law in other rulings I have a bridge in Brooklyn I want to sell you. However, no rulings have been "based" upon foreign law.
If you cannot see the difference between "consulted" and "based" then you need a good dictionary and some language lessons. There is a HUGE difference which ideology cannot overcome.