Boris, once more into the breach. Mr. Johnson — now  a back bencher— is a steward of the cause he made his own: Brexit. The latest reminder that Mr. Johnson is what passes for a conscience on Brexit comes amid news that Prime Minister Sunak is set to strike a deal with Brussels in respect of Northern Ireland. Mr. Johnson’s voice in the wilderness — calling for 10 Downing to keep the pressure on the Continent — is, in our view, the one to heed.

The original protocol was a codicil to Brexit struck by Mr. Johnson in 2021 to govern the flow of goods between Northern Ireland, the European Union, and Britain. While allowing for some measure of autonomy, it provides for the continued jurisdiction of European courts over the British Isles and precludes Westminster from pursuing unilateral alterations to the accord. All of this is too much of the continent for die hard unionists in Northern Ireland.     

The Brexit faction in Parliament, in sync with the unionist bloc at Belfast, has proposed a bill that would empower Britain to override the protocol on its own, without permission from Brussels. The Europeans argue that any alteration to the bill would amount to a violation of international law, and threaten legal action. Mr. Sunak’s hypothetical agreement would obviate such a bill. Until then, Mr. Johnson argues, Britain should not unilaterally disarm.  

The Daily Telegraph — for which Mr. Johnson once covered the European Union —  reports that the former premier believes it would be a “great mistake” to scrap the bill prematurely. Others agree. The home secretary, Suella Braverman, tells the BBC that the bill is “one of the biggest tools we have in solving the problem on the Irish Sea.” The leader of the Commons, Penny Mourdant, judged Mr. Johnson’s intervention to be “not entirely unhelpful.”

That bill is paused while Mr. Sunak parleys with the Continent. He does so against a backdrop of stalemate at the Stormont, the devolved parliament at Belfast. There has been no government there since Sinn Féin won elections and boycotted by unionist factions, demanding an arrangement less tied to Europe — more in the spirit of Brexit —  than the one originally struck by Mr. Johnson, a chimera that retained vestiges of European control. 

Mr. Sunak has thus far been circumspect. The Financial Times reports that British officials reckon that there are “hard yards” ahead before a deal can be struck. An EU official calls the bill supported by Mr. Johnson a “a loaded gun on the table.” It looks like more Tories — triple digits — are committed to keeping it there. The leader of the Belfast unionists demands that the Northern Irish retain a “say in making the laws that govern them.”

The EU can speak only bureaucratese. It is calling for  “structured dialogues between Northern Ireland stakeholders,” among whom the EU would include itself. That, though, lacks the tang of the Northern Irish demand for liberation. Mr. Sunak speaks of the “democratic deficit,” echoing the argot of his background in finance. We prefer Churchill’s “sunlit uplands,” but less important than parlance is policy. On this head, Mr. Johnson has it right.