Germany's firewall has become a fire exit. In Saxony-Anhalt, the CDU's plan is to walk out before its own MPs can vote AfD.

On 6 September, 43.8% of the voters of Saxony-Anhalt backed the Alternative for Germany. The AfD won 39 of the 83 seats in the state parliament in Magdeburg, according to the federal returning officer. The Christian Democrats, who have run the state for most of its existence, fell to 17.2% and 15 seats.

Seven weeks later the CDU has a plan for the moment, probably in mid-December, when the AfD's Ulrich Siegmund asks the parliament to make him Germany's first AfD premier. When the vote comes, the CDU's MPs will stand up and leave the room.

That is where Germany's famous firewall, the Brandmauer, has ended up. Not a wall. A door.

Why a party walks out of its own vote

The walkout is not a protest against the AfD. It is a precaution against the CDU.

On 6 October, the new parliament elected the AfD's Tobias Rausch as its speaker, the first AfD speaker of any German state parliament. He got 48 votes. The AfD and the left-populist BSW, which had promised to back him, have 44 seats between them. The CDU leadership had asked its 14 participating MPs to abstain. There were five abstentions, tagesschau reported. When the left-wing daily taz later asked every CDU member how they had voted, eight said they had abstained, according to MDR. Five abstentions, eight people claiming them. The arithmetic does not need a political scientist.

Friedrich Merz first warned against "hasty conclusions" and floated the idea of a "false flag operation" by other parties to embarrass his own. The other parties were not amused. In Magdeburg, the CDU group drew its own conclusion: in mid-October it decided, 14 votes to none, that its MPs would leave the chamber during the first two rounds of the premier vote, MDR reported. In those rounds Siegmund needs 42 votes, an absolute majority of all members, so his 39 need just three more. If no CDU member is in the room, no CDU member can be one of the three.

In other words, the leadership of a German party of government has concluded that it cannot trust its own MPs with a secret ballot, and has solved the problem by not letting them have one.

The man who wants to stay

One of them has already said no. Guido Heuer, a former leader of the CDU group, abstained on the walkout decision, citing legal concerns. He now says he will stay in his seat. His argument is hard to dismiss: in a secret ballot, walking out makes your choice public. Leaving the room is itself a vote, cast in front of the cameras. How he will vote, Heuer has not said. As a "convinced Christian Democrat", he said, he knows what to do.

Heuer wants "a politics of red lines" instead of a firewall, MDR reported: no coalition with the AfD and no formal toleration of an AfD government, but no ban on issue-by-issue majorities or a minority government either. Whatever you think of that, it is at least a position. The walkout is a choreography.

The third round

The plan also has a hole in it, and the CDU knows it. If the first two rounds fail, the parliament votes on dissolving itself. If that fails too, a third round follows, in which a simple majority of the votes cast is enough. Abstentions do not count, and neither does anyone standing in the corridor.

Run the numbers, as MDR did. If the CDU stayed outside, the BSW abstained as it has announced, and the SPD, Greens and Left voted against, Siegmund would win 39 to 24. So the CDU has promised that in a third round it would "of course" be in the chamber, as its leader and caretaker premier Sven Schulze put it. How it would vote then, Schulze would not say, beyond insisting the group would not help elect an AfD premier. If all four non-AfD parties vote no and the BSW abstains, it is 39 to 39, a tie the state constitution does not explicitly resolve.

Meanwhile there is no constitutional deadline at all. Schulze's outgoing government simply carries on in a caretaker role, more than three months after an election it lost badly.

The trap, described by the people caught in it

The sharpest description of the CDU's problem came from one of its own. Thomas Röwekamp, who chairs the Bundestag's defence committee, told Politico that the AfD "wants to annihilate the CDU in Germany" by "forcing us into a debate about how to deal with it in order to divide the party".

He is right. And the walkout is that debate, turned into parliamentary procedure. For two months the story out of Magdeburg has not been the economy of a state that is ageing and losing young people, or schools, or migration, or the energy prices that are driving people into the streets elsewhere in Europe. It has been abstention counts, false flags and who will be standing in which corridor. Siegmund, naturally, calls the walkout disrespect for the voters' will. He could not have scripted a better campaign.

A state CDU lawmaker, Chris Schulenburg, defended his colleagues to Politico: they distinguish themselves from the AfD "on the basis of substance", but do not exclude its MPs because the party "is not currently banned" and its members "were also democratically elected". That is closer to what voters can understand than anything said in Berlin. A party that wants to beat the AfD has to do it in the place where the AfD is winning: in arguments, in delivery, at the ballot box. It cannot do it by leaving the room, and it certainly cannot do it by treating its own MPs as suspects.

Firewalls are meant to stop a fire spreading. This one is being used to keep the CDU from seeing itself in the mirror. In December, whatever happens in Magdeburg, everyone will be watching who walks out, who stays, and how many votes Siegmund gets. The one thing the plan guarantees is that the CDU will once again be the story, for all the wrong reasons.