Here is the trouble with mainstream political parties adopting the policies of xenophobic or isolationist insurgents to win back votes: You can not cherry-pick such things. You become them.

This is happening to Britain’s Conservative Party, whose leader, Prime Minister David Cameron, is so anxious to stop defections to the UK Independence Party ahead of elections next year that he is mimicking its polices.

First came his promise to hold a referendum by 2017 on whether to leave the European Union (EU). Now there is the proposal, set out by Secretary of State for Justice, Chris Grayling, to give the European Court of Human Rights in Strasbourg an ultimatum: Either allow Britain to ignore the court’s judgements when it wants or Britain will withdraw from its jurisdiction altogether. Cameron says he will make that ultimatum if he wins a majority in elections next year. That amounts to a memo to Tory voters: If you are considering a switch to Ukip, don’t, because sticking with us will get Ukip policies enacted.

The European Court of Human Rights is the judicial arm of the Council of Europe, which Britain helped establish after the Second World War. It is not part of the EU; rather, it enforces the European Convention on Human Rights in 47 countries, from Dublin to Vladivostok. One founder, Winston Churchill, said the goal was to create a “united Europe whose moral concepts will be able to win the respect and recognition of mankind,” and to ensure peace on the continent.

The court has become the best tool available for extending the rule of law into countries that do not have it, providing ordinary citizens around Europe with recourse from bad court decisions, politicised courts and neglectful or tyrannical governments. Here are a few examples of what the court does:

A family in Turkey alleges that the state failed in its duty to protect their daughter. After 16 years of beatings by her husband and three restraining orders that were not enforced, she asked to be taken into a protective shelter, but was refused on grounds that she had children to look after. Her husband then shot and killed her. The case is in its early stages.

The head of an opposition party in Azerbaijan said he had been kidnapped, tortured and threatened with rape by masked police, after his party complained of fraud in the country’s 2003 presidential election. The court ruled against the Azeri state.

In 2011, the court found against Britain for holding a British citizen in jail without charge in Iraq for three years. Britain’s intelligence services suspected him of conspiring to attack British forces around Basra.

Ukip and many Tories say, with justification, that the court in Strasbourg has “mission crept” far beyond the original purpose of countering any resurgence of totalitarianism that Churchill envisaged. It now deals with everything from sexual discrimination to the deportation of alleged terrorists, showing how different the world is today from the 1950s. They are particularly incensed by rulings that overruled British law to insist prisoners have the right to vote, and restricted the state’s ability to deport suspected terrorists.

Grayling’s ultimatum, however, is disingenuous. The Council of Europe and its court could not possibly give Britain a special dispensation to ignore rulings, so he is simply signalling intent to withdraw. That is problematic, too, because leaving a treaty requires the consent of the other parties and the other signatories would not agree to that, either. “Leaving an international convention is pretty much impossible,” says Matt Qvortrup, a constitutional lawyer at Kings College London. “Only North Korea has done so when they — illegally — withdrew from the Non-Proliferation Treaty.”

Of course, Britain could join North Korea and ignore its treaty obligations. Britain has among the best legal systems in the world and leaving the court in Strasbourg would make only a marginal difference to Britons, whose fundamental rights would remain protected. The main effect would be to open the door for authoritarian regimes to leave, too, and finally be rid of a pesky foreign court that stands in judgement over their systematic abuses of law and power.

Russian President Vladimir Putin, for example, said last month that his country might leave the court, which in his view “merely fulfils some kind of political function”. His only hesitation was caused by uncertainty over whether Russia has the legal right to leave — he apparently has read his 1969 Vienna Convention on the Law of Treaties better than Grayling. With a British precedent in place, though, Putin’s hesitation would vanish.

Arguably, the European Court of Human Rights has never been so needed since the immediate post-war years as it is now, when authoritarians and ultra-nationalists are on the rise throughout Europe and the norms and institutions of the post-Cold War international order are under threat. Churchill was no European federalist, yet he was a strategic thinker. I suspect he would have considered his 2014 Conservative successors to be myopic.

— Washington Post

Marc Champion writes editorials on international affairs for Bloomberg View.