LONDON — The past 12 months have been a period of protest and disruption, a year when many political certainties across the Western world have been profoundly shaken, if not demolished. Regardless of all the ominous predictions, the next year must be a year of reconciliation and rebuilding.

The constitutional legal case seeking to force Prime Minister Theresa May to consult parliament before triggering Brexit should be seen in this light. The case — the “Gina Miller challenge” after its lead claimant, one of the authors of this article — is now before the Supreme Court in London.

The argument put forward by May’s government — that it can use ancient prerogative powers to bypass the sovereign British parliament — goes against the most basic pillars of the British constitution and endangers more than 400 years of sovereignty and democracy.

This legal challenge has a clear objective: to preserve the fundamental legal principle that only parliament can grant, diminish or remove the rights of British citizens. It also aims to bring legal certainty to the process of Brexit.

It was never intended to go against the will of the people as expressed in the June referendum on European Union membership. To the contrary, the challenge seeks to ensure that the will of the people is implemented with respect of the laws and the unwritten constitution of the United Kingdom. By seeking to ensure that the government respects and acts within the rule of law, the Miller challenge is profoundly democratic.

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What is at stake is not a small legalistic point; it is the very essence of British democracy and, more, the very essence of Britain’s success as a society, as a state and as an economy that is significant on a global scale.

“U.K. Plc” is successful globally, not only because the whole world measures time from Greenwich and speaks English, but also because people from all over the world see in British democracy and its rule of law the pillars of a reliable, civil and stable economy and society.

Investors from every corner of the world — Russia, China, Africa, Asia, the Middle East — flock to the U.K. to invest money, register companies, insure businesses, litigate, educate their children and buy property, precisely because of Britain’s stable democracy and its respect of the rule of law.

These values are found wanting in many parts of the world, but in the U.K. are taken for granted. They should be sacrosanct. A rushed Brexit in breach of the rule of law could undermine centuries of state and nation building, starting with the Magna Carta in 1215.

Similarly, the remaining 27 EU countries need to know that the U.K. has invoked Article 50 in a constitutional fashion before it can start negotiating the terms under which Britain will leave and then coexist with the EU.

Businesses that have invested in the U.K. need clarity on the terms under which they will be able to continue to operate. This will allow them to decide whether to continue to invest in Britain, or start relocating staff and facilities to where their continued operations will best be profitable and efficient.

Equally important is the future of the 3.3 million EU citizens living in the U.K. and the 1.2 million British citizens living in the rest of the EU. These 4.5 million people have acquired rights to live and work where they have chosen to establish themselves and their families in full respect of the law.

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From the day the outcome of the EU referendum became known, it was clear that there was no legal certainty as to whether the government could invoke Article 50 under the royal prerogative without consulting parliament.

People voted to leave in order to “take back control.” But invoking Article 50 without consulting parliament would be a fundamental violation of precisely the sovereignty that “Leavers” hold so dear.

Judgment will provide legal clarity to what has so far been an uncertain process.

In the U.K., parliament is sovereign, and it is parliament that enacted the European Communities Act of 1972 which took the U.K. into the European Community on January 1, 1973. It was also the sovereign parliament that ratified European Commission rules and passed laws establishing new rights for British citizens, such as the right to take residence in other EU countries.

In October, the High Court in London unanimously ruled in favor of Miller et al. And yet the government has sought to appeal to the highest court in the land. It argues that it can bypass parliament using prerogative powers reserved for international treaties and actions.

As Lord David Pannick, lead counsel for the Miller challenge, stated, “prerogative powers end where domestic rights begin.” After four full days of hearings in December, the 11 judges of the Supreme Court are expected to issue their final ruling in mid-January.

Regardless of how they rule, their judgment will provide legal clarity to what has so far been an uncertain process.

Gina Miller is a founding partner at SCM Direct. Ivo Ilic Gabara is the founder of Gabara Strategies Ltd. He tweets at @igabara