Political philosophy, like other realms of moral philosophy, deals with issues which cannot be settled by a formal test or procedure - such as a rule of law or the judgment of a political official; either because there is no rule or the rules are unclear, so that someone must first decide what the rule should be.
A classic issue of political philosophy arises from the decision by the British Government, in response to a national plebiscite, to leave the European Union. Put simply, the question is whether members of the UK Parliament have a duty to support the government by accepting the will of the people.
To understand this issue, and how it arose, one must first clarify the relevant law. That process began in mid-July 2016, when Gina Miller, a Guyanese-born funds manager, philanthropist and outspoken critic of hidden fees and other dubious investment practices, began proceedings in the High Court to protect statutory rights arising from membership in the EU.
No one, it seems, thought she had much of a case. Notwithstanding, on 3 November the British High Court shocked the government and the nation by ruling that Article 50, the legal provision which governs the Brexit separation process and which the government assumed it could activate using the prerogative powers of the Crown, requires legislative authority.
The decision in R (Miller) v Secretary of State for Exiting the European Union  EWHC 2768, rested on the Court’s ruling that legal rights created by parliament can only be taken away by parliament. It means the UK Parliament, which opposes Brexit, is free to ignore the plebiscite and pursue its own view of the nation’s interests, including those of later generations.
On the same day David Davies, the Minister of State for Exiting the European Union, told the BBC the government would now appeal because:
Parliament was sovereign and MPs had voted by six to one to give the British people the final say on whether or not to leave the EU…. The people, who were also sovereign, then delivered the biggest ever electoral mandate, to leave the EU.
This seemed a persuasive argument until United Kingdom Independence Party (UKIP) MP Michael Farage, the colorful leader of the Brexit movement, conceded that the plebiscite was (as the High Court found) an advisory procedure with no legal consequences. This did not, however, moderate his claim that Brexit might not succeed because MP’s were still opposed and the ruling could now be the start of a ‘deliberate wilful attempt’ to ‘betray’ voters.
The populist media took up this theme in a scathing attack on the court, with a Daily Mail front page showing portraits of the three judges above the caption ‘Enemies of the People’. The ruling had, it said, defied 17.4 million Brexit voters and could trigger a constitutional crisis’ (because) an unelected panel of out of touch judges had ruled that embittered Remain supporters in parliament should be allowed to frustrate the overwhelming (52% to 48%) verdict of the British public.
In due course Tory MP Elizabeth Truss, the Lord Chancellor who is responsible for the integrity and independence of the courts, reminded the media and public that the duty of a judge is, first and last, to uphold the law of the land. This is, however, unlikely to sway those who believe the essence of democracy lies in accepting the will of the people as sovereign; that governments, in the end, must do what the public wants.
This is the question of political philosophy now facing the UK Parliament: To what extent should public opinion define the duty of members? There may be no legal duty, but perhaps there is an implicit duty, based on democratic theory, to respect the will of the people, even if it is a slim majority with little knowledge of the consequences, and may change as these become more clear.
Most Brexit supporters take this for granted and many will see it as another conflict between ‘the people’ and elitist politicians; between democracy and the idea that those who hold power can impose their own views on the community. It adds to the distrust of institutional practice and ‘establishment’ politics, now seen as a world-wide phenomenon. This sense has been strengthened and focused by PM Theresa May’s commitment, unusual for a leader of the Conservative Party, to reduce inequality as a central aim of her government.