▁have ▁a ▁similar ▁effect . ▁If ▁an ▁action ▁of ▁Congress ▁or ▁the ▁ag encies ▁is ▁challeng ed , ▁however , ▁it ▁is ▁the ▁court ▁system ▁that ▁ultimately ▁dec ides ▁whether ▁these ▁actions ▁are ▁perm iss ible ▁under ▁the ▁Constitution . ▁ ▁The ▁Supreme ▁Court ▁has ▁indicated ▁that ▁once ▁the ▁Constitution ▁has ▁been ▁extended ▁to ▁an ▁area ▁( by ▁Congress ▁or ▁the ▁Cour ts ), ▁its ▁coverage ▁is ▁ir rev oc able . ▁To ▁hold ▁that ▁the ▁political ▁branches ▁may ▁switch ▁the ▁Constitution ▁on ▁or ▁off ▁at ▁will ▁would ▁lead ▁to ▁a ▁regime ▁in ▁which ▁they , ▁not ▁this ▁Court , ▁say ▁" what ▁the ▁law ▁is ". ▁ ▁S cope ▁and ▁theory ▁Cour ts ▁established ▁by ▁the ▁Constitution ▁can ▁reg ulate ▁government ▁under ▁the ▁Constitution , ▁the ▁supre me ▁law ▁of ▁the ▁land . ▁First , ▁they ▁have ▁juris diction ▁over ▁actions ▁by ▁an ▁officer ▁of ▁government ▁and ▁state ▁law . ▁Second , ▁federal ▁courts ▁may ▁rule ▁on ▁whether ▁coordinate ▁branches ▁of ▁national ▁government ▁conform ▁to ▁the ▁Constitution . ▁Until ▁the ▁tw enti eth ▁century , ▁the ▁Supreme ▁Court ▁of ▁the ▁United ▁States ▁may ▁have ▁been ▁the ▁only ▁high ▁trib unal ▁in ▁the ▁world ▁to ▁use ▁a ▁court ▁for ▁constitution al ▁interpretation ▁of ▁fundamental ▁law , ▁others ▁generally ▁depending ▁on ▁their ▁national ▁legisl ature . ▁ ▁The ▁basic ▁theory ▁of ▁American ▁Jud icial ▁review ▁is ▁summar ized ▁by ▁constitution al ▁legal ▁sch ol ars ▁and ▁histor ians ▁as ▁follows : ▁the ▁written ▁Constitution ▁is ▁fundamental ▁law . ▁It ▁can ▁change ▁only ▁by ▁extraordinary