HOW? they won’t even know how much people make!
One way would be to pass an emergency income tax law. It will start as an Emergency measure when they find out that they are not collecting enough because too many transactions are going underground or switching to “for business use”. It would probably be implemented as a version of the Flat Tax, say 10% of everything over $100k.
Since there would be an Emergency, and people need their social security checks, and the government workers need their paychecks, this would be about the only politically possible way to make up the shortfall.
And make no mistake, there will be a fairly large reduction in the retail base caused by a 40-50% sales tax. This reduction in volume will trigger an even larger drop requiring even higher sales tax rates. It is a terrible negative feedback system.
Maybe, if you make less than this targeted amount you just have to file a postcard that says you are below the amount with no other details maybe, just to get the votes of the “less fortunate”. Employers will be the ones that have to enforce the reporting for all their “rich” employees.
The rich don’t need the money anyway. /s
This will be hunky-dory with most of the dependent electorate.