JWK
A sales tax is an indirect tax, so the apportionment rules in the Constitution don't apply.
The Constitution stipulates, "No Capitation, or other direct, Tax shall be laid, unless in Proportion to the Census or enumeration herein before directed to be taken."
Sales tax is not a 'direct tax'.
Now, please take the time and go back to the top of the thread and read the words of our founding fathers with respect to any general tax laid among the States.
A sales tax is an excise tax, as it is applied to specific goods. There is no apportionment requirement to federal excise taxes. The words 'general tax' are nowhere to be found in the Constitution.