The SCOTUS rules on all sorts of controversies. Most often they rule on matters of procedure and statutory construction. Sometimes they rule on constitutional matters. Most cases that come to the SCOTUS are not momentous but boring, but occasionally there is a momentous case.
The SCOTUS has, for some time now, been very good at doing the following:
- waiting until there is a "circuit split"
(meaning lower courts deciding the issue
differently) on some kind of controversy
before hearing appeals
- then making the narrowest possible ruling
(emphasis on possible),
- thus often leaving some issues undecided so
that lower courts may develop jurisprudence
on the matter further before the SCOTUS need
clarify,
- which then allows the SCOTUS room to maneuver
if they make bad decisions (the SCOTUS does
not like to overrule earlier decisions,
something they call "stare decisis", meaning
what is decided is decided),
- and they do this by remanding to lower courts
to decide things the SCOTUS left undecided.
In this case the SCOTUS did not decide whether the plaintiff should get his property (or equivalent value) back. There's little doubt now that the Indiana courts will decide that the plaintiff must get his property back, and if not, the very first Federal court to hear an appeal will do so, because this follows from today's decision, but the Court did not decide this. Nor did the Court decide whether Indiana could take the balance of the seized property and the fine up to the maximum fine -- this is less clear, but since there is a conviction, sentence, and fine on record, it seems difficult to change the fine ex-post just to minimize the State's liability and/or change the then-defendant's punishment, for that ship has sailed.
As to oversight, yes there is, but it goes un-exercised now for a long time. Federal judges are appointed for life, but they can be left without a court or without a jurisdiction, the various courts' jurisdictions (including the SCOTUS'!) can be narrowed statutorily, court sizes can be changed -- all of this by simple majorities of both houses of Congress and Presidential approval (or veto override). There's also two ways to amend the Constitution to change SCOTUS decisions. But none of these things have been attempted in decades. The last time there was an attempt to use statutory avenues was in the 30s, when FDR tried to pack the SCOTUS, and the Senate killed the project. Before that we'd have to go back to the income tax amendment (the 16th), and before the Reconstruction Amendments (13th, 14th, and 15th).
The most notable case I'm aware of when Congress did away with courts for political reasons, was way back when Thomas Jefferson was President. Congress then closed about half the federal district courts and left as many judges court-less. Congress has changed the size of the SCOTUS, including shrinking it, from time to time, though I think all of that was in the 18th and 19th centuries, and never did they pack the court -- it was always changes of +-1 or +-2.
There's always a risk of court packing. It seems strange that the Constitution allows it by simple majority -- it feels like a bug.
A number of politicians have threatened to pack the court the first chance they get. Given our rather nowadays-frequent wave elections, it could very well happen. The filibuster in the Senate will be no protection for the minority in the Senate the day it comes to packing the court anymore than the filibuster stands for nominations to the court (it no longer does). But it's also not guaranteed to happen. It will be very costly to whichever party does it, and since we've had so many wave elections in recent decades, any court packing scheme simply might not last.