This piece by @repasi well expresses the doubts I have about the orthodoxy that no agreed UK/EU amendment of the WA is possible by (on the EU side) using the Art 50 procedure. verfassungsblog.de/avoiding-the-n…
The proposition that the EU could do so only by using other, more unwieldy, procedures would in practice make it impossible to move (by agreement) the date on which a transition extension had to be agreed (currently 1/7/2020). So the point is important.
As Rene points out, the proponents of the orthodoxy have to accept that that orthodoxy leads to the existence of an international treaty of practically indefinite duration that cannot be amended by consent. That is so absurd as to cast doubt on any argument leading to it.
