The European Union's executive has launched a previously unused procedure, aimed at safeguarding the rule of law in the 28-country bloc, in order to investigate controversial reforms passed by the new Polish government.
Here are the three stages of the procedure, which was introduced in 2014 to give the European Commission more options before resorting to the more drastic step of curtailing a member state's voting rights, foreseen under EU law.
In its first step, the commission will now collect and examine all relevant facts to determine whether the Polish reforms constitute a serious threat to the rule of law. If so, it will send its opinion to Warsaw, initiating a dialogue and giving Poland a chance to respond.
The EU's executive can decide at this stage to drop the procedure, because its concerns have been met, or it can proceed to the next phase.
At this stage, the commission can issue a recommendation, setting a deadline for Warsaw to address the problems identified. The recommendation will also be made public.
In a third stage, the commission would monitor Poland's response to the recommendation. If the issue is not resolved to the commission's satisfaction by the date set, it can resort to more serious measures foreseen under EU law.
The strongest response available falls under Article 7 of the EU's Lisbon treaty. This allows for a member state to have certain rights suspended, including its voting rights in the council of the EU's 28 member states if there is a clear risk of a serious breach of the bloc's fundamental values.
This move, which has been referred to as the "nuclear" option, has never been used against a member state.