Poland was where the second world war started and where the Soviet empire began to crumble. Now the country may once again play a crucial role in European history. A struggle between the European Commission in Brussels and the Polish government is shaping up as an existential test for the EU.

In December, for the first time ever, the commission started a formal procedure that could strip a member state of its voting rights. The Polish government stands accused of violating the EU’s founding principles, which include “democracy, equality, the rule of law and respect for human rights”.

The battle over Poland is turning into a test case over the strength of populism — not just in Europe, but around the world. Charles Kupchan, who ran the Europe department in the Obama White House, wrote last week: “With the United States missing in action, it is up to the European Union to defend the principles and practices of democratic society. The fate of Poland, Europe and the west is on the line.”