Teresa Villiers holds (September 5) that when Brexit happens there must be a reasonable chance the land border between the United Kingdom and the Irish Republic can be kept open.
But if not? Shouldn't politicians also be considering their response, rather than thinking it won't happen?
The border being kept open ultimately depends on the European Union.
And what if Brussels insists on ending the common travel area in these islands - a possible means of edging out the Republic, which it sees as a troublesome tax haven that siphons off money arising from commercial companies operating in the EU, but claiming the Republic as headquarters.
If a hard border is insisted on, with no preferential treatment above other European citizens for the vast number of Irish Republic citizens living in England and Wales, what then?