The comparison I've used before is if George W. Bush had, having failed to get his plan for modest privatization of social security enacted as legislation, authored a memo announcing to the IRS, Treasury, and DOJ that they were to use their discretion over collection of FICA, and instead reimburse all taxpayers 2% from that for their own personal investment (in other words, enact his failed legislative intentions by executive action).
It would have been enjoined, and every court that heard it would have laughed his administration out.