Berlin  - Chancellor Angela Merkel and her Christian Democratic Union (CDU) have lauded a compromise on migration policy as upholding the "spirit of partnership in the European Union" and a decisive way "to regulate and steer secondary migration." For the CDU's Bavarian sister party, the Christian Social Union (CSU), and Interior Minister Horst Seehofer, it was the only way to enforce an "asylum turnaround." The compromise deal looks anything but solid, however.

What does the compromise mean?

On the German-Austrian border, migrants whose asylum applications are the responsibility of other EU states will be prevented from entering Germany. They will instead to be held in so-called transit centres until they can be returned to the country responsible for them. Under the agreement, Germany will not send asylum seekers back without consulting the countries involved. If countries refuse to accept them, they will be sent back from the border "on the basis of an agreement with the Republic of Austria," although it is unclear how exactly this would take place.

How many cases are we talking about?

Media reports say that as of mid-June, Germany had taken in 18,349 asylum seekers already registered in the European finger print system Eurodac this year. The number is significantly lower than in previous years. The CSU, which is facing a challenge from the anti-migrant AfD in Bavarian state elections in October - wanted to send a signal, however, about strengthening Germany's borders. Why have both Seehofer and Merkel "won" this battle? Seehofer had threatened to reject migrants at the border even if the countries responsible did not want to take them back. Merkel wanted to avoid unilateral decisions that would foist off the problem on neighbours and instead to seek solutions with European partners. She expressed concern German border closures would result in other countries shutting their borders, thereby undermining the EU principle of free movement. The deal is now being referred to as the "fiction of non-entry."

Is there something to this contention?

In the regulations pertaining to residency law, it states: "The foreigner has first passed the border crossing point when he has left the control stations of the border police and customs behind him ... and is free to travel inland." If the migrant is put in a transit centre, the person in legal terms has not yet entered the country even if he has passed the control points.

Why is the talk now about airport procedures?

This refers to the practice at airports applying to asylum-seekers from countries that have been deemed as safe when they arrive by plane in Germany. Under German asylum law, the airport procedures mean that the "asylum proceedings are to be conducted before a decision on permitting their entry." The right to a proper asylum proceeding only takes effect when the migrant has gained some kind of residency. In effect, the airport proceedings amount to speeding up the decisions and rejections. Something similar is now foreseen for the transit centres. But it would likely mean that the migrants will not be able to leave the centres and instead will be interned there. Does this mean that no further ineligible asylum seekers will be coming to Germany? No. Firstly, it applies only to the German-Austrian border where at the moment only three crossing points are controlled, in addition to some dragnet operations in the interior. It is difficult to imagine that people who are picked up kilometres inside Germany will be sent to transit centres since they have de facto already reached German soil. In addition, asylum-seekers who arrive in Germany and did not register first in other EU states will be dealt with in the same way they were before and will not be sent to transit centres. Meanwhile, nothing will change on Germany's borders with other neighbouring countries.

What role is Austria playing?

The deal applies only to migrants who are picked up at the Bavarian-Austrian border. Austria is to take in all those migrants whose countries of origin do not accept administrative agreements covering their deportation from Germany. It is not yet clear how Vienna feels about this. The CDU-CSU deal will need to be negotiated with Austria. Where is there a potential for further controversy? The wording can be up for interpretation. "Asylum seekers for whom other EU countries are responsible" are, under the CDU-CSU accord, to be denied entry. This looks to be less far-reaching than what Seehofer was always demanding - that all those who had been finger-printed in other EU states should be sent back - because registration alone does not automatically mean that a state is responsible for asylum proceedings. The Dublin accord does not provide for an appraisal of jurisdiction. Meanwhile other criteria, such as where family members are located, play a major role

Now the question is, will the Social Democrats agree?

A key question. In 2015 the party - then in the previous coalition government - rejected the transit centres, also referred to as anchor centres. SPD leaders spoke of "arrest zones" that were neither feasible from an organizational standpoint nor legally conceivable. Now, however, the issue is not about blanket application to all arriving refugees but instead about relatively few cases of people without prospect of residency. The SPD wants a speed-up of procedures, meaning a stay at a transit centre of one week. Some on the party's left-wing are opposed. But the alternative, if the SPD rejects the deal, is a collapse of the coalition and then new elections. This spectre could well influence SPD thinking.