The fact that the UK government is now saying it will pass legislation that will break an international Treaty it signed and ratified little over a year ago, is very serious. It undermines Britain’s aspiration to be a globally trading nation.
All trade between nations rests, ultimately, on respect for Treaties and contracts.
Deliberately breaching commitments, freely given in a Treaty, undermines the whole structure of global relations between states.
If one cannot rely on a commitment in a Treaty, nothing is reliable.
The EU only continues to exist because its member states respect the Treaties that set it up ( as some seem to have forgotten in another context recently).
If the UK, by its breach of the Withdrawal Treaty commitments it gave on checks on goods going from Britain to Northern Ireland, forces Ireland to introduce checks on the Irish land border, in order to protect Ireland’s status as a fully complaint EU member, it will undermine the structure that has brought peace to these islands.
We could be living with the consequences of this long after Boris Johnson has passed from the political scene.