Fewer than 72 hours have passed since Dominic Grieve lost his job as Attorney General, and already the effects (or intentions) of this element of the reshuffle can be seen.

Nick Robinson has been briefed by someone that Cameron is exploring ways to shake the foundations of the European Convention/Court of Human Rights:

‘In recent weeks the prime minister was presented with a plan by a group of Conservative lawyers. It proposes a new law which would assert that Parliament and not the European Court of Human Rights was the supreme body.

Their report predicts that a so-called British Bill of Rights would either force changes in the way the Strasbourg court works or trigger a crisis which could lead to the UK’s expulsion from the international body which set up the court and which Britain helped to found – the Council of Europe.’

Grieve, Robinson reports, was blunt in his response – the idea was “a legal car crash” and “incoherent”. His argument is about the rule of law as he laid out in October in a speech at the Guildhall:

“…many of us will also have sympathy for the criticism that some EU rules or ECHR rulings have gone too far, and intrude into British practices and traditions that should be for us alone to change, should we choose by democratic means to do so.

But while we remain part of these institutions and remain bound by the rules which we helped to create, we must continue to be actively engaged, and to comply with our commitments. Moreover, if we are to remain secure and prosperous in this new century, the British body politic has to ensure it does not lose sight of the value in being a central player in developing the international system of mutually binding rules that determine how we as countries, companies and individuals conduct ourselves on matters that affect each other’s interests.”

In other words, if you want to be a member of a convention and a subscriber to a court, then you need to follow its rules. If you don’t want to follow its rules, then you ought not to be a member or a subscriber. This is the source of his point about legal coherence: why join only to ignore it?

It’s worth noting that Grieve has long been at pains to point out that he is not an unconditional supporter of the ECHR, though it’s fair to say he has a strong degree of sympathy with it. Despite his personal views, he makes a sensible legal argument: sign up to an authority and live by its rules and judgements, or leave and don’t.

But this is politics, not a court case. The debate at the heart of Government about what to do with the ECHR is more subtle than questions of mere logic.

The Prime Minister, as many have noted in furious ConHome comments over the years, is not a hardline eurosceptic – the man who warned against “banging on about Europe” did not set out to have a fight with Strasbourg. But as time went by the constant interference of the ECHR in what ought to be democratically controlled, sovereign matters offended both his principles (“it makes me physically ill to contemplate giving the vote to prisoners”) and the thing he prizes most of all: being seen to get on with the job. As Robinson notes today, the Qatada saga played an important part in convincing him he must address the issue somehow.

He could, of course, just leave the thing, tear up the convention and un-friend the euro-judges on Facebook. Many of us would be more than happy to see him do so. The counter-argument that such a step might encourage tyrants like Putin to behave badly is rather weakened by the fact that Russia, an ECHR signatory, is essentially waging war on Ukraine, another ECHR signatory.

However, politics is not just about what you do – it’s also about whether you are seen to do it. With trust in politics and politicians at an all-time low, simply saying “we’ve done this” is getting less and less effective. Some in Government are surely considering whether it would be more beneficial in terms of the polls to have a public battle with the ECHR – which is essentially the proposition put to Cameron by those Conservative lawyers mentioned in Robinson’s piece.

It’s a canny suggestion – there are headlines and votes to be won by such a fight. The technical argument is one thing, but in the court of public opinion (the only one which really matters as we approach the election) it’s far preferable to have an “Up yours, Delors” moment. If the Strasbourg apparatchiks choose to respond by attacking the difficult British for refusing to obey judgements that help terror suspects, then all to the good.

It would still run up against the legal arguments, of course. The court would tell us to do something, we’d say no, they’d issue a fine, we’d refuse to pay it – and then, the Grieve case goes, we would be a British Government undermining the rule of law. The implication of doing so would be greater than simply leaving the Convention – it would be to question the whole legality, constitutionality and validity of these supranational institutions. Consider it in those terms and it’s clear quite how far events have driven Cameron from his opposition to “banging on about Europe”.

The other question which is yet to be fully considered is what we would do instead of the ECHR and its monstrous child, the Human Rights Act. A paper by Dr Lee Rotherham for the TaxPayers’ Alliance explores some of the possibilities – including going back to the previous arrangement of relying on Common Law. The Prime Minister appears to be tempted by Rotherham’s Option 3 – withdrawing (eventually) from the ECHR and introducing a British Bill of Rights in its place.

That’s an evolution from the old policy, which Grieve supported, of introducing an ECHR-compliant Bill of Rights to replace the Human Rights Act. As critics pointed out, the problems lie in the way the Court interprets the Convention, not simply in the admittedly bad drafting of the Human Rights Act. As such, a British Bill of Rights outside the ECHR would be an improvement, but it is not without its own problems.

Not least, if we intend to assert the supremacy of Parliament when introducing a British Bill of Rights, it therefore follows that subsequent governments can simply change the Bill later on. Any pretence that this would be a scrap of written constitution, and therefore somehow immovable, would be just that – a pretence. Simply introducing the Bill would not be enough to protect it from Human Rights Act-mimicking amendment by Labour later on.

It could only be protected by building a strong, supportive majority among the public to make any attempts to water down or wreck the Bill politically unacceptable. To do that requires a long campaign, a high profile public debate about what should constitute a modern Bill of Rights, and therefore a protracted battle with Hacked Off, the political correctness lobby, left wing charities who want to prevent governments from ever reforming welfare and a host of others who would love to mould the Bill into an entrenchment of statism rather than freedom.

All that could be done, and would be worth doing for the eventual prize – but does the Government have the time, the energy and the will?