But last week, German Chancellor Olaf Scholz prevented Orbán from single-handedly blocking the opening of talks on Ukraine’s EU accession by asking the Hungarian premier to leave the room.

The move – allowing the 26 remaining leaders to take a unanimous decision in Orbán’s absence – has been hailed by some as an ingenious manoeuvre, but by others as a dangerous precedent that could permanently fracture EU unity.

Critical EU decisions on foreign policy, security, enlargement and finances require the unanimous blessing of all 27 member states, but abstention does not prevent a decision from being taken.

Scholz has called for limiting the use of constructive abstentions to “exceptional cases,” arguing that “we should definitely decide together whenever possible and come together.”

But with critical decisions on the EU’s future looming, Commission President Ursula von der Leyen has indicated leaders could be forced to explore other creative solutions to sidestep a possible Orbán veto as early as next February, when leaders meet again to try to seal a deal on a €50-billion long-term support package to Ukraine.

“Either we have an agreement by 27 or we will have worked on alternatives that we can then make operational when the time comes for this next council,” von der Leyen said last Friday, suggesting the bloc could consider an exceptional agreement between all but one member states to ensure cash still flows to Kyiv.

And with multiple decisions on Ukraine’s integration into the bloc requiring the unanimous blessing of all member states, EU leaders will likely be tempted to seek Orbán’s constructive abstention again.

Euronews asked two experts what this could mean for EU unity.

“Politically unprecedented”

This is technically not the first time a leader is absent during a European Council vote.

Leaders often nominate another leader on their behalf when other commitments prevent them from being present. British premier Theresa May also often constructively abstained from the Council’s votes during the years between the Brexit referendum and the UK’s official formal exit from the bloc. Former German chancellor Angela Merkel also abstained during a vote by the Council to appoint Ursula von der Leyen as Commission chief.

But this would be the first time one leader has signalled the door to another in a highly choreographed and politically charged move, explains Janis Emmanouilidis, deputy chief executive at the European Policy Centre.

“This is comparable in the technical sense, but not in a political sense,” he explained.

“But I would not say that this is a dangerous precedent,” he added. “Orbán was not forced to leave the room, but rather decided for himself. It opens an avenue for future situations where one leader is up against the rest to save face without derailing a majority decision.”

But according to Alberto Alemanno, professor of EU law at HEC Paris, last week’s anecdote raises questions as to whether Orbán left the room on his own initiative or upon Scholz’s demand.

“Regardless of who took the initiative, Orbán’s abstention may set a new practice enabling the European Council to maintain a display of unity at a time of unprecedented division,” he explains, suggesting the manoeuvre could be used again to push through decisions under the guise of unanimity.

Alemanno also points out that the voting rules, which require at least two-thirds of Council members to be present during the vote, technically allow up to nine member states to abstain without stopping the Council from adopting a decision, despite the limited appetite.

Divisive decisions on the near horizon

Both Emmanouilidis and Alemanno foresee difficult European Council summits ahead, where Orbán or other EU leaders could move to wield their veto power on key decisions on the bloc’s enlargement and the key reforms it will entail.

“There are so many subsequent decisions on Ukraine’s long road to EU membership that require unanimity,” Emmanouilidis explained.

“Lots of opportunities will be given to Orbán and potentially to other heads of state and government to use their right to veto,” he warned.

As early as March, all member states will need to unanimously endorse the so-called “negotiating framework” which will guide talks on Ukraine and neighbouring Moldova’s accession to the bloc. All countries must also vet progress across all chapters of the negotiating framework, providing Orban and others with multiple opportunities to halt the process.

Bulgaria, the EU’s smallest economy, used its veto to stall neighbouring North Macedonia’s EU membership talks for two years, over disputes concerning the rights of the ethnic Bulgarian minority.

“Despite abstaining from this vote, Orbán maintains his veto in stopping those negotiations from starting any time soon,” Alemanno added. “The Council has merely gained time before the real decisions on the next enlargement will be taken in Spring.”

The use of flexibility in unanimity voting also comes as the bloc considers revamping its voting rules in preparation for welcoming more member states, in fear the unanimity requirement would be severely stretched in an enlarged bloc.

The prospect of winding up unanimity voting is highly sensitive, particularly among smaller member states who fear their influence in the bloc would slip if they lost their right to a veto.

But as with critical upcoming decisions on its foreign policy, membership and finances likely to strain the bloc’s unity, we could see leaders forced to bypass unanimity even before the bloc enlarges.

French President Emmanuel Macron clearly set out his stall last week, claiming there is room in some scenarios to “make maximum use of the flexibilities offered by the treaties.”

“On the issues of the moment, we have to try to maintain our unanimity, to move forward, to discuss, to work,” he explained. “But then, for the future, I think we have the levers to be very innovative, without making a big bang of the treaty, and to invent things outside too.”