In the increasingly surreal second Donald Trump administration, a 29-year-old Salvadoran named Kilmar Abrego Garcia now embodies the most fundamental restructuring of the US constitutional order, arguably in its history. Mr Garcia is being used as a test case for the Trump administration to decouple Americans from the rule of law and protection of courts. His case may be operating at the margins of American society, but its implications potentially represent a redefinition of the relationship between the individual and the US government.