^ There’s a difference between simplifying a complex situation so that dummies can grasp at least some basic aspects of it and printing a misleading diagram in block capitals and primary colours, although it was honest of them to point out in the corner that the crayoning was done by people who are not exactly unbiased.
Perhaps a more accurate version would go
Can we vote ?
You haven’t checked whether voting would be consistent with the Constitution, as it stands.
What does the Constitution say ?
It says the vote would be illegal.
There’s no circularity to this argument. If they want to leave they either have to get the Constitution changed, which will involve some willingness on the other side, or they have to leave in defiance of the law, which in the past has quite often involved some people being shot.