Poland’s populist leaders came to power on a wave of nationalist feeling. Liberals trying to shame them into backing down will only make them dig their heels in.

The EU has given Poland an ultimatum: a one-month deadline to drop plans for judicial reforms, which Brussels says would be a violation of the rule of law, on pain of losing Poland’s vote in the European Council. The EU has never before used this “nuclear option” on a member state and it seems like the kind of legal threat that should surely bring Poland’s ruling conservatives to its senses after weeks of street protests over the measures.

Yet, those who have faith in the value of external pressure on the ruling party chairman, Jaroslaw Kaczyński, forget what brought him to power.

The day the measure subordinating the Polish courts to political interference was approved by the parliament in Warsaw, Donald Tusk, the president of the European council, who happens to be Poland’s former prime minister – and Kaczyński’s arch-enemy – issued a half-page statement. In it he managed to make six references to Poland’s reputation abroad. The reform, he said, would “ruin the already tarnished public opinion of Polish democracy.” Tusk failed to explain why retaining an independent judiciary might be a good thing, even when nobody’s watching.

Like many postcolonial societies, Poland has a residual sensitivity about what “the west might think about us” – this is especially prevalent within the middle-class electorate that Tusk was presumably speaking to. Yet over the last decade, this embarrassment anxiety has provoked a backlash from the Law and Justice party (PiS), which dubs it a “teaching of shame”. The party came to power in 2015 on the back of pride-boosting slogans such as “Poland will get off its knees” that massively helped expand its traditional electorate, the elderly and rural or small-town dwellers, to include a new group you could call the dignity-driven youth.

And now, PiS is likely to use the Brussels pressure to play the sovereignty card even more than it has previously done, the goal being to show Poles who holds legitimate power. Poland’s justice minister, Zbigniew Ziobro, framed his response to the EU decision in the language of pride: “I ask Mr [Frans] Timmermans to cut his insolence and arrogance, when he speaks about Poland and Poles. Poles categorically demand respect.”

Liberals and progressives are making a big mistake in thinking they can shame Law and Justice supporters with warnings about Poland’s diminishing status in the west. In fact, they are blowing the wind in PiS’s sails.

Yet, they are egging on pro-European Polish progressives with these warnings and that is likely to polarise Polish society even further.

That is because most people don’t vote but they may be motivated to by a new conflict between supporters of closer EU integration and Eurosceptics.

Poland is not like the UK, where the 2001 election turnout of 59% saw politics textbooks rewritten to include chapters on “the crisis of participation”. Voter turnout in Poland habitually ranges between 40% and 55%. In 2015, Law and Justice was elected by 5.7 million people – 19% of those with the right to vote. Usually, it is not the nominal majority that radical parties need to win, but the majority that stays at home.

Our society consists roughly of three groups: approximately a fifth of regular voters, a fifth of regular non-voters, and three -fifths who vote from time to time. When the latter group finally shows up to the ballots, its members are most likely to vote for the centre. Yet, these three-fifths gets easily offended – and some electoral campaigns are calibrated to disgust them so that they stay at home complaining about low standards of politics. By contrast, the “iron electorate” remains unimpressed.

The threatened EU sanctions are likely to lead to a polarisation of Polish society along the lines seen in the Brexit and Trump campaigns.

On the one hand, Poland is one of the most pro-European countries in the EU. For the past decade, support for the EU has ranged between 70% and 90%, with recent polls showing 88% support. These are not just empty declarations. The single biggest anti-government protest carried the slogan, “We are and will be in Europe”. It gathered 30,000 people (according to the government) or 240,000 (according to the organisers).

Yet, Poles’ affection for the EU is not unconditional. In this, one of the world’s most homogenous societies, 51% say they would rather quit the EU than accept any plan for refugees allocated by the EU. The EU’s threats are likely to lead to a further polarisation of Polish society. Fear is the fuel, it has greater mobilising power than hope or the protection of the status quo. Both sides deploy it: the strongest fear that PiS can mobilise is Muslim refugees, while the strongest fear the opposition can generate is that of having to quit Europe. In other words, the anxiety of cosmopolitans about being cut off from the liberal world versus conservatives’ fear of accepting “the other”. Brace yourself for the next battle over our globalised world.