How to download the full ruling of USA Supreme Court cases?

[Zenaan Harkness]

Can this be done?

For example, this quote and "case" reference, should have some context:
"Jurisdiction, once challenged, cannot be assumed and must be
decided." [Maine v. Thiboutot, 100 S. Ct. 250]

How do I find the document containing that quote?

That quote and reference can be found by google on many sites in many
documents, but only as the quote - the full source document/ ruling
would provide the context, which would be more useful.

Some examples of URLs with the above quote (besides many others):
http://freedom-school.com/lewis-mohr/bowden-petition-and-challenge-to-jurisdiction.pdf
http://www.nationallibertyalliance.org/how-beat-any-court-case
http://thegetjusticecoalition.blogspot.com/2007/05/cp-6.html