EU nations are to be vetted annually on their adherence to the rule of law, in a renewed attempt from Brussels to stop governments from firing independent judges and packing courts with pliable supporters.

In an effort to stop democratic backsliding, all EU countries will be subject to annual monitoring on the rule of law, the European commission announced on Wednesday, one day after its incoming president, Ursula von der Leyen, sought to assuage critics of her appointment with a pledge to uphold democratic values.

Elected with a wafer-thin majority, Von der Leyen, said she fully supported an “EU-wide rule-of-law mechanism”, as she sought to tackle accusations she would be beholden to nationalist governments in Poland and Hungary that supported her surprise elevation to the top job.

Details on that rule-of-law mechanism were spelt out in a policy paper published on Wednesday by the commission vice-president, Frans Timmermans, who has repeatedly clashed with Poland’s ruling Law and Justice party over its judicial changes.

Hungary is also facing the EU’s most serious disciplinary procedure since the European parliament declared a “systematic threat” to the rule of law in 2018, although the process has languished in the EU’s council of ministers.

Timmermans announced the commission would publish an annual rule-of-law report, which would cover all member states to help detect “emerging rule-of-law problems wherever they appear”.

Germany and Belgium made a similar proposal in March, in order to counter the accusation that central and eastern European countries were being unfairly targeted. “The EU’s role in this area must be objective and treat all member states alike,” says the paper that will be discussed by EU ministers on Thursday.

The commission is embroiled in an unprecedented legal battle with Poland over the integrity of Polish courts, which led to last month’s landmark European court of justice ruling that Warsaw’s decision to lower the retirement age of judges was unlawful.

Since coming to power in 2015, Law and Justice has argued that far-reaching changes to the judiciary are required to remove judges who served during the communist era.

In a separate move, the commission announced the next step in another legal case against Poland on a law that allows judges to be subject to disciplinary charges over their rulings, a measure denounced as having a “chilling” effect on judicial independence.

The commission said on Wednesday it would take the Polish government to court if Warsaw did not act to change the disciplinary regime within two months.

That deadline falls before the arrival of Von der Leyen, who is scheduled to take office on 1 November.

The first-ever female commission president was criticised by some Socialists and Greens, who claimed she would be a weak defender of the rule of law.

Law and Justice’s backing of Von der Leyen’s nomination fanned that idea, with the party’s official Twitter account quoting the Polish prime minster, Mateusz Morawiecki, describing her as a good candidate to work out compromises.

An EU source said the strengthened approach had been embraced by Von der Leyen, adding: “If anything we are trying to tighten the net, not make it looser.”

Von der Leyen told MEPs that the commission would “always be an independent guardian of the treaties. Lady Justice is blind – she will defend the rule of law wherever it is attacked.”

She emerged as a compromise candidate after Poland and Hungary led opposition to Timmermans, a Dutch socialist, who ran in a pan-European campaign to replace Jean-Claude Juncker.

In a statement Timmermans said the rule of law had “come under attack in several ways” in the past five years, without naming specific countries. “The European commission has been fighting hard to resist these attacks with the tools available to us, and will continue to do so. Today we have decided to further strengthen our toolbox, to promote, protect and enforce the rule of law.”

Von der Leyen has revealed little of how she intends to handle upcoming negotiations on the EU’s seven-year budget, with some member states wanting to tie EU funding to the rule of law, a measure that could hit Poland, a net beneficiary of European money.