THERE are three basic political stances on immigration. The first two are the easiest to hold as a politician: to be overwhelmingly for or against permeable borders. Sit in either of these camps and you can easily exude what one might call the three Cs: confidence, crispness and clarity.

German politics is a case in point. At a recent demonstration in Berlin supporters of the far-right Alternative for Germany party marched under banners with slogans like “No passport, no entry” and “Islam doesn’t belong in Europe” while counter-demonstrators from the city’s club scene partied and protested to techno music under the mantra “Refugees are welcome here”. Both sides knew their arguments and made them with gusto.

A similar pattern is visible in the party-political landscape. Of Germany’s seven main parties the two with the most momentum and swagger at the moment are those that represent the two poles of the open-to-closed spectrum: the pro-immigration Greens on one end and the anti-immigration AfD on the other. In times of stormy debates on the subject, these parties easily project the three Cs. Everyone knows where they stand.

Yet most voters conform to neither pole. Parties like the Greens or the AfD can together count on a combined 10-20% of the electorate. But to win the election-deciding middle, politicians must find balance between the strong liberal arguments for immigration—cultural, economic, humanitarian—and the worries, justified and otherwise, that many voters hold on the subject.

It all amounts to a sort of trilemma. When it comes to immigration, politicians can be responsive to voters’ worries and (let’s not be coy about it) prejudices; they can be liberal in their principles; they can be clear about where they stand on the subject. But it is fiendishly hard for any of them to be more than two of the three.

Many mainstream politicians therefore end up in the rather muddy middle: trying to reconcile liberal instincts with responsiveness to voters’ concerns. The attempt can often make them look like pianists trying to tune their instruments in the middle of a concert, constantly twiddling the lever to find the right pitch while the musicians around them play blissfully clear, pitch-perfect notes.

That played out in German politics recently when employees of a branch of the Federal Ministry for Migration and Refugees (BAMF) in the northern city of Bremen were accused of taking bribes to wave through up to 1,200 immigrants with questionable claims to asylum. The scandal widened this week when it was revealed that two extremists were included among those they let in.

As usual, the pro-closed and pro-openness sides of the debate have clear positions: the AfD has demanded a formal inquiry; the Greens (joined on this occasion by the socialist Left party) are against one, recoiling from the far-right’s support for the measure. As ever, both sides are confident, crisp and clear.

And as ever, the parties in the middle are anything but. Andrea Nahles, the new leader of the Social Democrats (SPD), has been trying to win back anti-immigration voters. In early June she told a party gathering in eastern Berlin that Germany “can’t take in everyone”. In response to the Bremen scandal she admitted that: “We all knew that the BAMF was not at all equipped to cope with this number of refugees.” The AfD promptly started quoting her line in its statements and social media posts.

But the SPD leader has also opposed an inquiry into the scandal, deeming it too late and too slow. Christian Lindner, leader of the pro-business Free Democrats, is for an inquiry but issued his demand in the AfD’s slipstream, giving the impression that he was merely aping the far-right’s stance. MPs in the SPD and Angela Merkel’s CDU are gradually coming round to the case for an inquiry too. But again: too slowly, too passively. The mainstream piano is still being tuned in the middle of the concert.

This reflects a wider problem for politicians seeking mass appeal. According to Jim Messina, a former Obama strategist, the average voter thinks about politics for four minutes a week. In such a short space of time the hemming and hawing of the muddy middle is inaudible. Simple tunes do best. In an age when open-v-closed themes like immigration are rising in salience, those with clear stances on that spectrum are gaining ground.

The question is: can the mass political mainstream break the mould? Can it be clear, confident and crisp from a position balanced between voter concerns and the virtues of full openness? Or does that balance make it like the piano tuner at the concert: condemned to twiddle the lever finding a pitch while others strike perfectly formed notes? Three principles suggest themselves, drawing on the muddle in which German parties of the middle have found themselves in recent days.

First, move fast to set the agenda. The subject of an inquiry into the BAMF’s failings has only become so controversial because the AfD was the first to demand it. If mainstream parties had demanded it first, it would not have acquired its totemic significance. The AfD would have been sidelined. Instead those parties dithered and let the far right make the running.

Second, distinguish more confidently between valid and invalid arguments. A reluctance to give the AfD and other anti-immigrant groups credibility helps to explain why the German mainstream has handled the BAMF scandal so cautiously. Yet demanding an inquiry into the failings at the ministry should come as easily to those who subscribe to liberal principles as does criticising those who seek to twist the saga for their nativist ends. There should be no contradiction between championing immigration and upbraiding abuses of the system.

Third, have the courage of your convictions. A really ambitious liberal-realist politician would have seen in the BAMF scandal an opportunity to make afresh the case for immigration to Germany: by deploring the abuses not just in the name of “ordinary Germans” but also on behalf of the hundreds of thousands of recent immigrants who have played by the rules; who bribed no officials; who got to Germany with the sort of determination, verve and ambition that a comfortable but ageing country in the heart of Europe badly needs.

None of these points is a panacea. The responsiveness-liberalism-clarity trilemma is mostly inescapable. But navigating it starts by recognising its existence and the fact that, having decided as a politician that one’s two primary loyalties are to voter concerns and liberal values, one will necessarily sacrifice some confidence, crispness and clarity. And that one’s task from then on is to mitigate this sacrifice.