[justshutupandtakeit]

Its power ends with allocating jurisdiction and establishing salaries, organization and size of courts. However it cannot tell those courts what to do or how.

[texasbluebell]

That's not at all what Santorum was saying.

He said this Article and Section gives Congress the power to reign in the judiciary.

Someone has given him advice that I'd like to know more about.

[Cboldt]

However it [Congress] cannot tell those courts what to do or how.

Congress establishes rules of procedure, and other details (e.g., sentencing requirements, statutory remedies, statutory causes of action, etc.), certainly more than "allocating jurisdiction and establishing salaries, organization and size of courts."