ANGELA MERKEL returns from last night’s European Council summit with a European agreement on new immigration controls and a trilateral arrangement between Germany, Greece and Spain to help curb secondary immigration to her country (see here for a full overview by my colleague in Brussels). In Berlin one question now dominates: is the package “wirkungsgleich”? 

The term translates roughly as “equivalent in effect”. Horst Seehofer, Germany’s interior minister, used it in an interview with the Süddeutsche Zeitung newspaper last weekend to describe the bar the chancellor’s European negotiations must clear for him not to start turning back “secondary immigrants” registered in other EU countries at German borders. Mrs Merkel strongly opposes that measure for fear that it could lead to a domino-effect of new, unilateral border policies throughout the continent. 

Mr Seehofer’s Christian Social Union (CSU), a conservative Bavarian party that sits with Mrs Merkel’s Christian Democrats (CDU) in the Bundestag, had been using the threat to distance itself from the chancellor ahead of state elections in its home state in October, at which the anti-immigrant Alternative for Germany party is expected to do well. Amid talk of a formal split of the decades-old CDU-CSU alliance, on June 18th the Bavarians gave Mrs Merkel two weeks to come up with her preferred “European solution” to the secondary migration quandary—or risk that break if she failed. 

Now the CSU has the answer, but its response has been strikingly hesitant. Manfred Weber, the CSU leader of the centre-right block in the European Parliament, has observed: “the EU summit has achieved a big step towards a better immigration policy”. But he is on the more Merkel-friendly wing of his party. Among the Merkel-sceptics at the top of the CSU, Mr Seehofer has declined to comment for the time being and Markus Söder, the minister president of Bavaria who has urged on the interior minister’s brinksmanship, has merely called for calm reflection on the results of the summit.   

That heightens the sense that the momentum is once more with Mrs Merkel. The chancellor was visibly relieved as she appeared before cameras in Brussels early this morning; a mood echoed by loyalists in her CDU, who have spent the day busily talking up her achievements. Even some Merkel-sceptics like Mike Mohring, the CDU leader in the eastern state of Thuringia, have welcomed the package. At a press conference this afternoon Mrs Merkel described it as “more than wirkungsgleich”.

This cautiously upbeat mood reflects not just the chancellor’s modest negotiating achievements, but also new polling for the broadcaster ZDF showing that most Germans want Mrs Merkel to remain chancellor and, by an overwhelming margin, agree with her that immigration strains should be handled at a European level. Meanwhile the CSU’s attempts to win over Bavarians by taking her on have transparently failed: polls show fewer, not more, voters in the party’s home state now plan to support it in the autumn. 

To be sure, Mrs Merkel is not safe yet. The CSU’s bellicose rhetoric over the past weeks—characterising turning back secondary immigrants as the only credible answer to the problem—could make backing down awkward. Even today Andrea Lindholz, the CSU chair of the Bundestag’s interior affairs committee, said that the measure should remain on the table. Meanwhile the chancellor’s deals are hardly watertight: the European Council statement is vague; her new arrangement with Madrid and Athens relies on secondary immigrants being detected on the German-Austrian border, where there are currently only occasional controls on certain routes; there is not yet a bilateral deal with Italy, the largest source of secondary immigration to Germany.  

Yet what Mrs Merkel has achieved is not nothing, and set against low expectations may well be enough. Tonight she talks to CSU and CDU leaders. On Sunday afternoon, just ahead of a crunch meeting of the CSU leadership, she will record a television interview to sell her negotiating achievements to the public. The chancellor will reportedly hand Mr Seehofer the task of finalising the full network of bi- and tri-lateral deals that she claims can control and reduce secondary immigration to Germany. 

In other words the chancellor wants to press home her advantage while she can: binding in Mr Seehofer; daring the CSU to look unreasonable in the eyes of voters; yet avoiding triumphalism in order to give the Bavarians the maximum rhetorical room to back down with dignity. The next days will tell whether they will use it.