DW: Ms. Tempel, Chancellor Angela Merkel has responded to Turkey's  detaining of two German citizens by saying it was perhaps necessary to "rethink" Turkey policy "even further." Is this an adequately clear statement?

Sylke Tempel: The chancellor is not known for heated rhetoric. However, I'm certain she has already gone through a few options in dealing with Turkey. With Erdogan, we have someone who is dismantling democracy after he at first expanded it, with respect to empowering religious Turks, for example. Turkey is also strategically important to NATO, given its geographical location in a volatile region. We do not want Turkey turning towards Russia. We want to continue to have influence. That doesn't happen with someone like Erdogan simply by beating them down. A gentler approach is necessary.

Read more: Sigmar Gabriel: 'Turkey will never join EU' under Erdogan

In your view, what would be the appropriate steps for Germany to take?

With these kinds of opponents, you have to always see what you can do to make things hurt and, where possible, bring them to their senses. However there is never, really never, any guarantee that this will have any effect. Such rulers whip up their people into a frenzy, using slogans about not bending and remaining steadfast. However, Turkey is only hurting itself that way. Everything they have won at the economic and political level is being put at risk, including Turkey as a partner for Europe. This means that the German government's reaction has been so far appropriate: It has increased travel and security notices and is turning up the heat. But there is no guarantee this will lead anywhere.

What do you make of Erdogan's actions? What are his goals?

 It would be nice to be able to make out his strategic intentions. Apparently, it just seems that Turkey is holding hostages. Erdogan made this explicitly clear in the case of Deniz Yucel. The question remains, of course, to what end these hostages are being held. Is it to prevent Germany from granting asylum to Turkish military officers accused there of being part of the coup? This severely underestimates the legal situation. Here in Germany, asylum applications are reviewed. If it is clear that the person cannot be sent back for fear of political persecution, then asylum is granted. Clearly, there are elements in Ankara not thinking from the perspective of the rule of law. They clearly believe they can put the German government under pressure this way.

Read more: Open letter from jailed journalist Deniz Yücel's wife: Open the door, it's me

How do you judge Turkey's approach? What are the long-term effects?

The tragic thing is that Erdogan was perhaps doing some of the right things at the beginning. He continued on with reforms from the previous government, which led to economic growth. Turkey had initially become an actor we could trust. Now there is the impression that this is all being gambled away. The current economic data do not look good for Turkey. Trust is vital for the economy as much as it is for politics, and that is built most of all through rule of law. This also means that you have to have confidence that you won't be detained at the airport in Antalya if you fly to Turkey. In all, the result is an enormous loss of trust.

Taking a wider view, you could say the same thing about Russia.

Russia annexed Crimea, thereby fulfilling a central project for the government. There's no turning back for Russia. This kind of politics enjoys public support, which is strongly influenced by the media. The consequence, of course, is weaker economic standing and technological modernization. It is the less well-off sections of society that pay the highest price for this, which paradoxically are most supportive of the government.

Sylke Tempel is an author and editor-in-chief of International Politik, the magazine of German Society on Foreign Relations (DGAP), where she serves on the board.

The interview was conducted by Kersten Knipp.