No, we MUST have an amendment that forbids congress from enacting both. Otherwise, they’ll repeal the income tax, implement the sales tax and later they’ll say that the “crisis” is so dire they need the income tax...oh, oh, oh, just for TWO years and then it sunsets, we promise! And then two years later...well, you know the drill.
You have to think of politicians as crack addicts. And you have to limit and restrict them accordingly.
See #28.