As Boris Johnson announces his resignation today, he fires the starting gun on the process to select the fourth Conservative prime minister since David Cameron took office in 2010.
Any change of leadership can have major implications for government policy, and Union policy is no different. Whoever succeeds Johnson will have to grapple with profound constitutional questions, to which their predecessor has often never adopted a consistent approach.
As things stand, there are at least two major axes upon which any incoming leader could strengthen, weaken, or upend the Government’s strategy on the Union. The first, of course, is Northern Ireland.
As we have observed previously, the Prime Minister changed the dynamic on the Protocol when he charged Liz Truss, a leadership contender, with taking over from David Frost in the negotiations. Whilst there were other factors that play, the outcome has been skipping straight over Article 16 to unilaterally adjusting the Protocol in primary legislation.
Given how controversial it is, and the big-picture signal it sends about our relationship with the EU, the future of the Northern Ireland Protocol Bill will doubtless come into focus during any leadership contest. Suella Braverman has already indicated that the situation in Ulster will be a priority for her.
This might make life difficult for candidates looking for some sort of reset of our relations with Brussels. They might not have wanted to pick this battle – but will MPs or the membership back anyone proposing to so visibly capitulate on something so important?
Less high profile, but also important, is the question of personnel. Brandon Lewis hasn’t played to the gallery as much as some of his predecessors, but has been a very effective Secretary of State. In particular, he is notable for having proven prepared to grasp the nettle on issues such as legacy.
His resignation is a loss to the Government and to the Province, and it would be a shame if the post returned to being a sort of sinecure for uninspiring loyalists with no particular interest in Ulster, as it was under Theresa May.
Then there’s the question of Scottish independence.
Just this morning, Nicola Sturgeon revealed that Johnson has refused her permission to hold an independence referendum sanctioned by Westminster. Quite right too.
But what about the longer-term view? One never got the impression that the incumbent ever had a strategic vision for how to defend and indeed fortify and rebuild the United Kingdom over the long-term.
This approach was embodied in the chaotic life and death of the Union Unit, with both Luke Graham and Oliver Lewis eventually forced out by court putsches. Then there’s the fact that the Government took the trouble to pass the UK Internal Market Act, and has since barely used it.
Now Michael Gove, the man who was in charge of the Union policy, has been sacked, whilst two of the three territorial secretaries of state have resigned.
Unlike the Protocol, there is no totemic Bill here to focus minds; it would potentially be easy enough for this topic to slip out of focus as the next leader tries to steady the ship and grapple with the war in the Ukraine and the cost-of-living crisis.
This must not be allowed to happen. MPs with a close interest in the future of the country – I’m thinking specifically of the 70-strong Union Research Unit – must organise to make sure the Union is front and centre in the leadership contest to come.