Can MPs really be given a vote on whether to enter the backstop?

The prime minister is trying to sell her Brexit deal to doubting Conservative MPs by offering them a “parliamentary lock” on the bit they don’t like, the backstop.

Let’s remind ourselves what the backstop is and why they don’t like it.

It’s a legally binding guarantee to keep an open border in Ireland after we leave the EU. Tory MPs don’t like it because we can’t get out of it except by signing a permanent trade deal that guarantees the same thing. Even Jeremy Corbyn has criticised it for that reason.

Theresa May could try telling her MPs that avoiding a hard border in Ireland is something they should want – but a lot of them don’t agree. They think it would be a price worth paying for a “real” Brexit – although they tend to argue in public that a hard border could be managed by technology and no one would notice it.

Instead, she is telling her rebels that they can have a vote on whether to go into the backstop, should it ever be needed.

This is spin. The withdrawal agreement contains a choice at the end of the transition period, the end of 2020. If the long-term trade deal with the EU has not been negotiated by then, and it seems likely that it would not have been, there are two options. Either the transition period could be extended, or the backstop would come into effect.

Which course should be followed has to be agreed between the EU and the UK. In other words, the EU has a veto over our choice. But the UK would have to decide which option to seek and May’s “offer” is simply to allow parliament a vote at this point, which is what might have been expected to happen anyway.

So it is not a “lock”, and it does not get round the fact that the backstop will still be the fallback option. If the UK opts to extend the transition period, at most by two years to the end of 2022, and if, when that expires, there is still no long-term trade deal, then the backstop will still come into effect.

Of course, the UK could decide to ignore the backstop and simply impose a hard border with Ireland, but that would be to repudiate the withdrawal agreement. This is an international treaty and we have a sovereign right as a nation to pull out of it, but that would have serious consequences.

Any country that goes around binning international agreements would become, in effect, a rogue state, and other countries would be wary of signing new deals with it. If we did that, it would not be possible to negotiate any kind of trade deal with the EU.

That is not what May is proposing, although some Brussels officials initially thought it was. They thought she meant MPs would have the chance to repudiate an agreement to which they had already agreed. That is the trouble with spin. If you are trying to pretend something is what it is not, people might assume you mean something else altogether.