LONDON -- The United Kingdom's government warned lawmakers not to try to "thwart the will of the people" after the Supreme Court ruled Tuesday that Prime Minister Theresa May must seek the approval of Parliament before starting the formal process of leaving the European Union.
The 8-3 decision forces the government to put a bill before Parliament, giving members of the House of Commons and the unelected House of Lords the chance to debate and alter the terms of the U.K.'s exit from the EU.
The government insisted that its timetable of starting the talks by the end of March remained on track.
"Parliament will rightly scrutinize and debate this legislation," David Davis, the government's secretary for the EU exit, told the House of Commons after the ruling. "But I trust no one will seek to make it a vehicle for attempts to thwart the will of the people or frustrate or delay the process of our exit from the European Union."
The U.K.'s departure was mandated by voters in a June 23 referendum.
May's government fought hard to avoid putting the matter before Parliament, in part because amendments to the legislation could delay May's timetable and force her into complicated concessions with her own lawmakers before she even sat across the table before the other 27 members of the EU.
May holds sway in the House of Commons, but the House of Lords in recent years has stalled dozens of pieces of legislation with which they disagreed, including an attempt by May's predecessor to impose welfare cuts on the vulnerable. The government backed down after the delay.
The lawsuit was considered the most important constitutional case in a generation because it centered on the question of who ultimately wields power in the U.K.'s system of government: the prime minister and her Cabinet, or Parliament.
May had said she would use centuries-old powers known as royal prerogative to invoke Article 50 of the EU treaty and begin two years of exit talks. The powers -- traditionally held by the monarch -- permit decisions about treaties and other specific matters to be made without a vote of Parliament.
The prime minister argued that the referendum gave her a mandate to take the U.K. out of the 28-nation bloc and that discussing the details of her strategy with Parliament would weaken the government's negotiating position.
Financial entrepreneur Gina Miller sued to force the government to seek parliamentary approval. Leaving the EU, she said, would change the fundamental rights of citizens and this can't be done without a vote of lawmakers. The Supreme Court agreed.
"The referendum is of great political significance, but the act of Parliament which established it did not say what should happen as a result, so any change in the law to give effect to the referendum must be made in the only way permitted by the U.K. Constitution, namely by an act of Parliament," Supreme Court President David Neuberger said in reading the decision, which was approved, 8-3.
"To proceed otherwise would be a breach of settled constitutional principles stretching back many centuries," he said.
In its ruling, which upholds an earlier decision by the High Court in London, the Supreme Court noted that Parliament had approved the 1972 legislation that enabled the country to join the EU and incorporated European law into British law. Leaving the bloc would take away from British citizens a number of rights that had been granted by the bloc.
As a result, "the government cannot trigger Article 50 without an act of Parliament authorizing that course," Neuberger said.
no part for 3 nations
The government did win one argument on Tuesday, with the ruling that the legislatures of the nations that are a part of the U.K. -- Scotland, Wales and Northern Ireland -- do not need to be consulted on the U.K.'s exit.
While the U.K. government has ceded authority over many local issues to these bodies, responsibility for international relations still rests with the government in Westminster. "Relations with the EU are a matter for the U.K. government," Neuberger said.
The government of Scotland, where voters overwhelmingly supported continued EU membership, has been an outspoken opponent of the prime minister's plans for leaving the EU.
"There are some fairly serious questions about how the U.K.'s constitutional settlement operates, not least the lack of democracy at the heart of the houses of Parliament," Stephen Gethins, the Scottish National Party's spokesman on Europe in the British Parliament, said in an interview. "All this raises quite substantial questions about the future of the union."
The strongest words of protest arose from the nations of the United Kingdom whose voters opposed leaving the bloc. In Scotland, the first minister, Nicola Sturgeon, said Tuesday that the case for a second referendum on independence was growing ever stronger.
"It's becoming clearer by the day that Scotland's voice is simply not being heard or listened to within the U.K.," Sturgeon said.
The Scottish National Party, which is the third-largest party in the House of Commons, already has pledged to put forward 50 amendments.
In Northern Ireland, where the fragile 1998 Good Friday Agreement that ended decades of sectarian conflict is predicated on membership in the EU and an open border with Ireland, the decision not to give its Parliament a vote risks aggravating the sectarian divide, officials said.
"Brexit will undermine the institutional, constitutional and legal integrity of the Good Friday Agreement," said Gerry Adams, the leader of Sinn Fein, which represents the Catholic nationalist community in Northern Ireland. "Our stability and economic progress," he said, "are regarded as collateral damage."
Labor leader Jeremy Corbyn said his party wouldn't frustrate the process but would seek to amend the legislation to make sure the government is held "accountable."
The prime minister's office is expected to submit a tightly worded bill to Parliament as early as this week, and if all goes well, May will begin a two-year, irreversible process of exit negotiations with the EU by the end of March.
"There's no going back," Davis told Parliament later Tuesday. "The point of no return was June 23."
Lawmakers from across the political spectrum have made clear that they want to be involved from the start.
"I and many others did not exercise our vote in the referendum so as to restore the sovereignty of this Parliament only to see what we regarded as the tyranny of the European Union replaced by that of a government," Stephen Phillips, a member of May's Conservative Party, said when the case was first filed.
Plaintiff Miller, co-founder of SCM Direct, an online investment manager, had argued the case wasn't about blocking a British exit but about "democracy" and the "dangerous precedent" that a government can overrule Parliament.
"This case was about the legal process, not about politics," Miller said in a news conference outside the Supreme Court.
Miller said she was "shocked by the levels of personal abuse that I have received from many quarters over the last several months for simply bringing and asking a legitimate question."
Miller has said she was threatened with murder and rape by "Leave" supporters, who have accused her of trying to sabotage the withdrawal.
For Miller, who lodged the case along with hairdresser Deir Dos Santos, the court's decision meant vindication after months of threats to her security that followed her involvement in the case.
Information for this article was contributed by Danica Kirka of The Associated Press and by Katrin Bennhold and Sinead O'Shea of The New York Times.
A Section on 01/25/2017