Another day, another emergency debate on Theresa May’s decision to participate in the US-led bombing of Syria. Jeremy Corbyn has chosen to fight on territory that unites the bulk of the Labour party, leading not with whether the air raid was right in principle but whether the Prime Minister ought to – from a moral rather than a constitutional perspective – asked Parliament first.

The Labour leader thinks he both has the answer – yes, she should have asked first – and the solution in his proposed War Powers Act, which would limit the power of a PM to act militarily without seeking parliamentary approval first.

But as the ongoing row over Generation Windrush and the continuing paralysis of the government's Brexit legislation shows, there is a wider problem with our unwritten constitution than just what the Prime Minister can do in the world elsewhere. As Jess Elgot writes in the Guardian this morning, almost half of the bills required to manage Brexit have yet to be introduced to parliament – among other things, because the government fears defeat.

That means MPs are likely to have to vote without a clear understanding of what Brexit means when the final deal comes before parliament. Now it's true to say, from voting its leverage away by passing Article 50 so meekly, to the large number of Conservative MPs who voted through the hostile environment policy who are now astonished to learn that the result is a hostile environment, that MPs have done a poor job of using the constitutional powers they do have.

But a constitutional settlement where the executive can take contentious legislation to the corner flag in order to force rebels to back down has big problems that go well beyond the need to codify who can do what as far as peace and war are concerned.