On Monday, parliament will vote to participate in the European arrest warrant. Or, more precisely, parliament will vote not to stop participating in the European arrest warrant. Actually, to be strictly accurate, parliament will vote to approve a mechanism by which the UK will stop participating in the European arrest warrant on 1 December and then immediately re-participate in it a fraction of a second later. (EU treaties are complicated like that.)

Whatever the technical ins and outs of the thing, Conservative backbenchers are unimpressed and many will rebel. Quite how many is uncertain. Scores would like to, but habitual anti-Cameron dissenters are playing down expectations of a record-breaking insurgency. The upcoming byelection in Rochester and Strood and the proximity of a general election campaign have put a seasonal premium on loyalty. The measures will pass in any case because Labour and Lib Dem MPs will support them. So the value of revolt in this instance is gestural.

In the eyes of militant Eurosceptics, the government is once again capitulating to Brussels and trading away sovereignty: undermining the supremacy of UK courts by allowing continental judges the power to spirit away suspects for trial in (ghastly) foreign jurisdictions. Supporters of the arrest warrant – prominent among them the home secretary – say it is an essential crime-fighting tool. Terrorists and gangsters don’t stay conveniently within national borders so police need continent-wide powers to nab and extradite.

Aside from the rights and wrongs of this specific policy, the whole episode provides an intriguing and salutary glimpse of the future for opponents of Britain’s EU membership.

The “Brexit” brigade tends to present rupture from Brussels as a clean break; the final step in a long journey of emancipation. Released from the shackles of continental bureaucracy, the UK can then contemplate a fresh life of buccaneering, free-trading, independent enterprise.

But one of the first things that the newly liberated country would have to do is negotiate terms of trade with its former EU partners. And in order to do that it would have to enter into all sorts of agreements – on trading standards, subsidies, safety regulations, contract enforcements, etc – that very closely resemble the single market of which the UK is currently a member.

The Brexit scenario involves opting out of everything in order to selectively opt back into lots of things, which is exactly the model currently being played out with the arrest warrant. Under the Lisbon treaty the UK negotiated a right not to sign up to the full justice and home affairs “pillar” of EU law on the understanding that it would pick and mix those items it deemed essential. Unsurprisingly, some of those turn out to involve a greater degree of cross-border collaboration and legal harmonisation because, well, it’s the 21st century and that’s how globalised economies and societies function effectively together.

At the moment, the hardline sceptics can declare themselves staunchly against anything that smells integrationist without positing alternatives because they are still in the principled unpicking stage of Britain’s entanglement with Europe. What they don’t seem so eager to contemplate is the re-stitching stage – the inevitable process of deciding what level of entanglement they might find acceptable.

The danger, as pro-Europeans never tire of pointing out, is a scenario akin to Norway’s “fax democracy”. Politicians in Oslo, lacking a seat around the Brussels table, await news of changes to trading rules and regulations that are decided in their absence and then, since they want the privileges of access to European markets, have to implement them anyway. Sceptics say that is a fate for small countries and that mighty Britain would get a more balanced arrangement out of its post-EU negotiations.

That may well be the case, but it is extremely unlikely that Britain would be able to choose the terms of its future cooperation with the EU and not face push-back from member states. The UK will still be expected to concede things in return. As a foretaste, discussions over the justice and home affairs opt-back-in were delayed because Spain raised objections connected to the status of Gibraltar – just the kind of tricky subject that goes unnoticed when everyone is part of the same EU and then becomes extremely awkward when someone decides unilaterally to change the rules of the game. In the event of a Brexit negotiation, a UK prime minister would find his path strewn with rocky problems ranging in scale from Gibraltar upwards.

None of them is insurmountable, say the Better-Off-Outers, and the prize of liberty would be worth having. The sceptics’ current objective – their “transitional demand” in Marxist parlance – is to force David Cameron to spell out more clearly what kind of deal he imagines doing in Brussels that would make EU membership palatable. They want to know what he really means by “renegotiation”. In reality, the kernel of implacable Conservative MPs know that there is no deal available to satisfy the urge for total emancipation from the European yoke. The more they push Cameron to spell out his terms, the clearer it becomes that no magical “third way”, EU-lite arrangement is plausible, and so the closer the party gets to accepting exit as an explicit policy goal.

And yet this process lets the sceptics off the hook of explaining which parts, if any, of Britain’s relations with the rest of Europe, enshrined in current treaties, would have to be reconstituted if the UK walked away. As the European arrest warrant debate shows, pick’n’mix Europe is a messy business that requires compromise on both sides.

The sceptics are happiest when pointing to the features of the EU they reject and putting pressure on the prime minister to agree with them. But only the most fanatical Ukippers indulge the notion that Britain can just sever its ties with the continent and demand free-trade privileges in the manner of an imperial power dictating terms to a colonial client. Even a negotiated Brexit would involve some pooling of sovereignty and deference to European institutions. After the opt-out comes the opt-back-in. Cameron isn’t the only Conservative who dodges the question of how much Europe he can stomach. The sceptics are in denial too. Total separation simply isn’t on the menu.