I should have done a little more scratching before I posted earlier. The Constitution uses terms “raising revenue” and “appropriations” where taxes (fees, penalties, etc.) are concerned.
Granted, even under today’s loose Federal jurisprudence.
It would make sense for someone to challenge that tax as being unconstitutional.
But before that can happen, somebody has to be charged the tax.
Barack doesn’t want that kind of court case and neither, apparently, do a lot of Republicans (for different reasons). Maybe Congress will pass a bill excusing people from the tax and actually get Barack to sign it.