The European Union is taking legal action against Poland’s right wing government over court reforms it fears will undermine the independence of the country’s common courts.

The action taken by the European Commission could lead to Poland being hauled before the 28-nation bloc’s highest court, the European Court of Justice, and eventually given a fine.

On Wednesday, the cCommission said it could trigger Article 7, a legal process of suspending Poland’s EU voting rights, if Warsaw went ahead and passed a contested Supreme Court Bill.

Opposition parties say the law will erode the independence of the judiciary and undermine democracy.

Poland’s nationalist government has rejected Brussel’s objections as blackmail and unjustified criticism.

The legal action had been expected after Polish President Andrzej Duda signed into law a measure that allows the justice minister to unilaterally replace the chief justices of the common courts.

Tens of thousands of protesters gathered in Warsaw and cities across Poland for candlelit vigils as the law was passed. They claim it violates the Polish constitution.