As the British struggle to choose a new prime minister and, in effect, a new government team, a huge delusion runs through much of the media comment and public debate.

This is quite simply that, whether Britain leaves the European Union with an agreed deal, with the “no-deal” (which in fact means with a string of issue-specific arrangements and mini-deals) or just stays in the EU, some kind of new sovereign control can be gained over its laws and government that will change things beneficially. We must “regain self-government,” goes the cry.

The delusion is fed by numerous examples of poorly judged and EU-inspired overregulation, as well as by the irritating superiority of EU law in British courts. It is fueled by tiresome and cumbersome procedures that a club of 28 countries has to go through to reach decisions and by the often perverse rulings of the European Court of Justice and the European Court of Human Rights. Ironically,the latter in reality has nothing to do with the EU, and will still be there, leave or remain, although few commentators bother to explain that.

Indeed, this last point illustrates the great delusion with crystal clarity. In today’s deeply interdependent world, the whole idea embodied in such ringing metaphors as “taking control,” “making our own laws” and “getting our country back” is fundamentally, intellectually and factually flawed.

Laws and institutions that have no connection with EU membership are expanding across the planet daily. They are part of the rules-based order that now stands between all of us and international anarchy. Almost every law passed in an open nation has to take constant account of both other countries’ laws and of higher agreed legal frameworks. No man is an island and no island (in this case the United Kingdom) is an island. A binding weave of behavior at every level shapes almost every aspect of ordered daily life and its governing laws. It will continue to do so whatever Britain’s relationship with other trade blocs, networks or neighborhood communities. Brexit will make only a marginal difference. The world of pure sovereign control has gone forever.

Today almost everything has its international dimension, whether it is food, diet, water, energy, lifestyles, birth, marriage, relationships, death, school, health, leisure, traffic and transport, skills, training, sport, policing, crime or the very air we breathe.

To every major issue of the 21st century — the march of technology, climate and environment, ethnicity, terrorism and crime in the streets, political alienation, unstable hyper-capitalism,ecological disaster or the rise of illiberalism — national governments acting alone have no answer. All progress has to be by agreement and cooperation with other parties and other nations.

Pity, therefore, the new British prime minister. He will have first to be a master of illusion and perform the seemingly impossible trick of extracting Britain from the EU. Then he will have patiently to explain that his powers are far more limited than the media or the public clamor begins to comprehend.

Woolly-headed media inquisitors keep asking the two rivals — Boris Johnson and Jeremy Hunt — to guarantee that Brexit will take place by Oct. 31, regardless of what arrangements have been reached. Neither have the power to give such a guarantee. That will be up to Parliament, where their Conservative Party has no majority.

Then the winner will have to reveal that unless Britain is attempting to become a kind of hermit kingdom, life will continue to be governed by a network web of international rules and procedures not very different from what went before.

Hardest of all will be to explain that both national identity and local identity, for which greater recognition is so loudly demanded, actually rest on conformity with the international and globalized context and its unavoidable disciplines. Some of these may have a less European and more global flavor, some will be just as intrusive or more so.

This is grand paradox of the digitalized, globalized age. The instant communication and unparalleled connectivity that most of the human race now demand, and that the giant platforms bestriding the globe now deliver, has created a contradictory puzzle. More independence depends on growing interdependence. The growing populist nationalism and localism increasingly craved almost everywhere is driven and enabled by the same forces that are globalizing and homogenizing humanity. The demand for being “us,” for having control, only has substance if it goes hand in hand with acceptance of the woven reality of higher rules and controls that are just managing to hold the modern world together.

Complicated? Very. Counterintuitive? Yes. Almost impossible to get over in an age of polarized simplicities and media exaggeration? Certainly.

Yet somehow the message must be persuasively conveyed and made acceptable if stable government is to be delivered, outrage assuaged and society to remain governable. Shortly a new British prime minister is about to discover whether the task is possible.

David Howell is a Conservative politician, journalist and economic consultant. He is chairman of the House of Lords International Relations Committee.