Poland’s political crisis deepened on January 10 after President Andrzej Duda pledged to have the two arrested former MPs of the Law and Justice (PiS)  party released from custody.

Mariusz Kaminski and Maciej Wasiks were convicted in December for abuse of power while leading the CBA, Poland’s anti-corruption bureau, in a corruption case dating back to 2007.

“They are crystal honest people … I will not rest until they are released from prison,” Duda said in a televised address. 

The PiS camp says Kaminski and Wasik are “political prisoners” and their arrest and previous stripping of their MP status constitutes a “coup”.

The power struggle in Poland comes after the new government, headed by Donald Tusk, promised to “restore rule of law”, which it says was compromised by PiS tinkering with the judiciary system, poor lawmaking, and the creation of institutions of questionable legal status.

The case of the two detained MPs indeed highlights Poland’s legal chaos after the PiS government. The former ruling party claims that a decision by one of the chambers of the Supreme Court upholds the status of Kaminski and Wasik as incumbent MPs while the arrest was unlawful.

But the government says that the Supreme Court chamber that issued the decision is not a court of law. The government refers to a December judgment by the Court of Justice of the EU that said the chamber – which was created by PiS – cannot guarantee impartiality and independence.

Meanwhile, another Supreme Court chamber – about which there exists no legal controversy – confirmed Kaminski and Wasik were no longer MPs in a decision contested by PiS.

It is unclear how Duda plans to have the MPs released from custody. The president had pardoned them in 2015, but some legal experts disputed the pardon because Duda granted it before an earlier court sentence against the two MPs became legally binding. A new pardon would create a risk to Duda of admitting that the original pardon was flawed.

"The [2015] pardon is valid," Duda said in his address, adding that it also meant that Kaminski and Wasik are still MPs.

Parliamentary Speaker Szymon Hołownia warned the president on Wednesday against plunging Poland into “a deep constitutional crisis”. 

Duda's defence of the two convicted MPs also confirms that he has decided to be a staunch opponent of the new government, perhaps intending to eventually take over as PiS leader, rather than take a compromise position in the hope of landing a top international job.

Duda has already delayed Tusk’s appointment as PM and used his veto powers to block the budget bill, which the government used to help overhaul state broadcaster TVP.

As Kaminski and Wasik remain locked up, PiS held a solidarity rally last night. Another, expectedly bigger, rally is taking place on Thursday. Kaminski also said he was going on a hunger strike.

The two MPs should formally be replaced in the parliament by PiS candidates who won the next biggest number of votes in the October election but it remains unclear if the replacements will accept their mandates as that would mean agreeing to Kaminski and Wasik losing theirs.