The Iran-Contra scandal from the Reagan administration comes to mind. Congress explicitly de-authorized the executive from funding the Contras in Nicaragua. T

The Iran-Contra scandal from the Reagan administration comes to mind. Congress explicitly de-authorized the executive from funding the Contras in Nicaragua. The executive kept doing it anyway. Nobody faced any consequences, though Congress at least made a lot of noise about it. That's kind of ineffective, but not to this level where Congress is just fine with blatant illegality.