The current furore over the Withdrawal Agreement, has got me re-reading how Eamon da Valera, starting in 1932, progressively violated and then dismantled the 1921 Anglo-Irish Treaty and weathered the "Economic War" that followed. https://www.irishexaminer.com/opinion/commentanalysis/arid-30839044.html

Two historical echoes.

- Da Valera saw the 1921 Treaty, a "withdrawal agreement" if you like, as not having achieved full independence, and not truly binding as it was imposed

- Britain, the hegemonic trading partner, restricted access to its market to push Ireland to fold

The historical lessons from the 1932-1938 dismantling of the Anglo-Irish Treaty would seem to be:

- treaties viewed as imposed are less likely to stick

- serious costs in overturning them

- trade retaliations fail to re-impose them

- geopolitics, like by 1938, move things on

Obviously, the analogy is vastly imperfect and not to be taken too seriously, and of course Twitter is an extremely bad place for such thought experiments.

But I do think these historical parallels are interesting.