As the results of the recent German election came in, a familiar pattern took shape. A broadly unpopular centre-left political party was voted out — due, in no small part, to its immigration policies and perceived economic failures — in favour of a centre-right party who pledged to adopt a “stronger” approach to borders and migrants, and to restore the nation to its former prosperity.

Lurking in the wings, meanwhile, is growing far-right movement that cannot overtly be courted by the governing parties, but whose popular appeal is implicitly acknowledged in the way they frame their policies and rhetoric.

For decades, the “firewall” (die Brandmauer) has stood between the far-right Alternative for Germany (AfD), on one side, and the centre-right Christian Democratic Union and the centre-left Social Democratic Party, on the other. But forces from with without, and political tactics from within, seem intent on testing whether that non-cooperation agreement should continue to hold.

So is a “firewall” — which seeks to limit the parliamentary influence of the far-right — the right way to defend a constitutional democracy, or does it undermine claims of democratic legitimacy?