Berlin and Mecklenburg Votes Test Germany’s Anti-AfD Firewall and Merz’s CDU Grip

German voters in Berlin and Mecklenburg-Western Pomerania go to the polls on Sunday, September 20, in two regional elections that have become a stress test for Germany’s mainstream-party firewall against the far-right Alternative for Germany — and for Chancellor Friedrich Merz’s authority inside the Christian Democratic Union.

The immediate stakes are regional: who governs the capital and who controls the northeastern Land of Mecklenburg-Western Pomerania. The broader question is national. After AfD’s September 6 breakthrough in Saxony-Anhalt, another strong performance would increase pressure on the CDU to explain whether its categorical refusal to cooperate with AfD can survive repeated state-level shocks — especially where the far right is strong enough to shape coalition arithmetic but remains formally excluded from power.¹²³

Merz has publicly held the line against cooperation with AfD, but the political cost is rising. CBS News reported that the CDU is debating how impermeable the “firewall” should be as AfD gains influence in regional parliaments, with some conservatives questioning whether the party should reject not only coalitions but also legislative majorities that depend on AfD votes.¹ That distinction — no coalition versus no reliance on AfD at all — could become harder to maintain if Sunday’s results leave mainstream parties dependent on broad, ideologically strained alliances.

Merz’s authority is on the ballot, even if his office is not

The two elections do not directly decide Merz’s chancellorship. But they come as his standing has already weakened. CBS News described Merz as under severe pressure after the Saxony-Anhalt result and noted that he canceled a planned trip to the United Nations General Assembly as the regional votes approached.¹ Euractiv reported that Merz summoned the CDU federal executive committee to Berlin for election night, seeking a unified response to what party strategists expect could be a difficult evening.²

Le Monde framed the Berlin and Mecklenburg-Western Pomerania elections as a matter of “political survival” for Merz and the federal coalition, citing discontent inside the CDU and speculation over whether a poor CDU performance could revive discussion of a change at the top.³ ARD’s tagesschau put the internal party stakes bluntly: if the CDU clearly misses its goals, the chancellor’s position could become uncomfortable, especially if Berlin is lost and the party performs badly in Mecklenburg-Western Pomerania.⁵

For now, Merz has received public backing from CDU state premiers, a show of support also noted by CBS News and Le Monde.¹³ But that support may depend on limiting the damage. If Sunday produces another AfD surge, Merz’s critics could argue that his strategy has neither revived the CDU nor stopped voters from moving further right.

Mecklenburg-Western Pomerania: the sharpest firewall test

Mecklenburg-Western Pomerania poses the more acute arithmetic problem. Le Monde reported that AfD was polling at 37%, more than double its 2021 result of 16.7%, while the CDU was near 7% and uncomfortably close to the 5% threshold required to enter the regional parliament.³ Euractiv also placed Mecklenburg-Western Pomerania at the center of the pressure on Merz, noting that polls showed the CDU close to the threshold and AfD near or ahead of the governing SPD.²

If AfD finishes first but remains excluded by all other parties, the next government would likely depend on a combination of mainstream and left-of-center forces willing to govern around it. That would preserve the firewall. But it would also underline the paradox facing German parties: the stronger AfD becomes, the more unusual and potentially fragile anti-AfD coalitions may have to be.

For the CDU, the worst-case scenario is not only AfD strength but CDU marginalization. A result near or below the 5% threshold would weaken the party’s claim to be the principal democratic alternative to AfD in the east. ARD reported that anything near 10% would already be viewed inside the CDU as comparatively good in Mecklenburg-Western Pomerania, underscoring how low expectations have fallen.⁵

Berlin: no clear frontrunner, few easy coalitions

Berlin is a different kind of test. The capital’s race is close, local issues such as housing and security dominate, and AfD is not expected to have a realistic path to power. But coalition arithmetic could still become complicated if several parties finish close together and mainstream parties continue to rule out cooperation with AfD.⁶

Deutsche Welle reported that Berlin is heading into one of the closest state elections in its history, with the CDU, Die Linke, AfD and the Greens clustered closely in polling and mainstream parties excluding cooperation with AfD.⁶ Le Monde reported that the CDU and Die Linke were both around 20% in voting intentions, while AfD could double its 2021 Berlin result of 9.1%.³

That makes Berlin a symbolic contest for Merz as well as a local one. A CDU win would give him a quick argument that AfD’s Saxony-Anhalt momentum can be contained and that the CDU can still win competitive races. A loss — particularly if paired with a weak showing in Mecklenburg-Western Pomerania — would reinforce the impression that the CDU is losing ground on multiple fronts: to AfD in the east, to the left in the capital and to internal doubts at the federal level.

The firewall’s dilemma: stability versus voter pressure

Germany’s “firewall” against AfD has long been a core convention of postwar democratic politics: mainstream parties refuse to enter coalitions with the far right or depend on it for governing majorities. CBS News reported that all major German parties support that red line, while noting that CDU debate is intensifying over how absolute it should remain.¹

Sunday’s elections will not end that debate. If AfD performs strongly but is locked out of government, supporters may present the result as evidence that voters are being ignored. If mainstream parties form broad coalitions to keep AfD out, those governments may prove harder to manage and easier for AfD to portray as establishment cartels. If CDU figures soften the firewall even incrementally, Merz could face resistance from moderates and coalition partners — and risk normalizing the party he has vowed to oppose.

This is why the Berlin and Mecklenburg-Western Pomerania votes matter beyond their combined population share. Le Monde noted that the two Länder account for just over 6% of Germany’s population, but the timing — two weeks after Saxony-Anhalt — has turned them into a national political test.³ The official Berlin election site confirms the September 20 vote mechanics for the Abgeordnetenhaus election, including polling-place lookup and sample ballots, but the political significance now reaches far beyond ordinary state administration.⁸

What to watch on election night

Three indicators will shape the national reading of the results.

First, whether AfD’s support continues to climb. A strong AfD showing in both Länder would deepen the sense that Saxony-Anhalt was not an isolated eastern protest vote but part of a broader pattern.

Second, whether the CDU can claim a defensible result. In Berlin, that means remaining competitive for the mayoralty. In Mecklenburg-Western Pomerania, it means staying comfortably inside parliament and avoiding the symbolism of near-exclusion.

Third, whether coalition options remain workable without AfD. The more fragmented the results, the more pressure there will be on parties that disagree sharply on policy to cooperate to maintain the firewall.

For Merz, the immediate danger is not a direct constitutional challenge. Germany’s system makes removing a chancellor difficult, and CBS News noted that a Bundestag no-confidence move would require agreement on a successor.¹ The more plausible risk is political erosion: a chancellor who remains in office but loses authority over his party’s strategy, campaign message and discipline on the AfD question.

Sunday’s votes will therefore test two linked propositions: that the CDU can still lead Germany’s mainstream right while refusing any cooperation with AfD, and that Merz can enforce that line after another electoral shock. If either proposition weakens, the firewall may remain formally intact — but under far greater strain.