It is the place you go to - to stop the GOV - as has been done say 1000 times on various changes to stuff done by POTUS - and indeed reversed 95% of the time due to sloppy process (lots of labor and EPA type stuff)
Courts help us "understand" what the law says
When the decision swings "left" the DEMS are accused of writing law
When the decision swings "right" the REPS are accused of writing law
Reality - with bias built in (or preferred way - method - philosophy - of reading constitution) - the judges try and answer the question of did the GOV follow the law (APA type stuff lots of the time - process) or re the constitution
Again - I do not believe a lot of law is written but I do believe 100% of the controversial decisions are accused of being written law
Forget the exact stat - but I think something like 90% of cases in a session are decided unanimously or nearly so as the law and interpretation are simple