A difficult diplomatic drive

Symbolically, the timing could scarcely have fitted better. Frank-Walter Steinmeier left an international conference in Rome on combating the so-called "Islamic State" to travel for Tehran, just as testy talks over Syria's protracted war got off to the shakiest of "starts" in Geneva.

Writing for the Welt am Sonntag weekly, Steinmeier had rebutted criticism of his trip to two of the world's more notorious rights abusers and regional rivals, saying that all foreign policy required a degree of tolerance and realism. In Rome, however, he told fellow ministers that he would broach uncomfortable issues on the visit.

"We understand national interests, but there is a national responsibility that goes beyond this, a responsibility for the Middle East region," he said in Rome.

Omid Nouripour, foreign policy spokesman for the Greens in Germany's parliament, told DW in a statement that for Steinmeier to act as an honest broker between the two sides, "equidistance" would be required. "That would include stopping all arms deliveries and loudly addressing rights concerns in both countries," Nouripour said.

Saudi Arabia is a prolific purchaser of German military equipment, while prior to the longstanding international sanctions, which are now being rolled back, Germany was also Iran's largest trading partner.

Difficult diplomacy, entrenched enmity

Initially, only Saudi Arabia had stood on Steinmeier's February schedule, given his recent visit to Iran after the international atomic accord. However, developments early in the year prompted the foreign ministry to add an Iranian stopover to the agenda.

Long-testy ties between Riyadh and Tehran took a further turn south on January 3, when more than 100 people - including prominent Shiite cleric Nimr al-Nimr - were executed in Saudi Arabia. Combine this with the war in Yemen directly involving Saudi troops and thought to involve Iranian support for the Houthi rebels, the ongoing Syrian civil war and the chaos in Libya, and you're left with an entrenched proxy war on several fronts between the region's two Islamic superpowers. Against this backdrop, what can Germany's top diplomat even hope to accomplish?

"I think the most important thing would be to succeed in reducing the current tensions between Riyadh and Tehran," Stefan Liebich, a foreign policy expert for the opposition Left party in the Bundestag, told DW. "For it was a major setback at the start of the year, after the execution in particular of the Shiite cleric in Saudi Arabia, when the two major players in the region cut their ties. That's because we need them to achieve a ceasefire in Syria, to get out of this awful war in Yemen, and we need them for Libya, too."

Next up on Liebich's list of hopes for the visit, that the Social Democrat foreign minister would make references "in both countries" to human rights abuses. "In this century, in our civilized world, people can't just be executed, body parts can't be cut off, all of this is no longer acceptable - and we have to say so clearly."

'A false symbol of normalcy'

In Riyadh, Steinmeier will visit the Jeandrivah Heritage and Cultural Festival, with Germany this year's partner country. As if to remind him of the diplomatic difficulties of the moment, the festival includes a display about the civil war in Yemen, in which a Saudi-led coalition intervened in 2015.

"The enhancement of the festival provided by the foreign minister's presence is a false symbol of normalcy, " said Nouripour of the planned appearance, while his colleague in parliament's foreign policy committee, Liebich, stressed that "we're not forgetting Yemen."

"In committee, we brought up the conflict with Mr. Steinmeier repeatedly, and we also demanded that he cannot stay silent on this issue in discussions with Saudi Arabia, or indeed with Iran, who incidentally are supporting the Yemeni rebels," Liebich said. "People are dying there. At the end of the day, they're even being killed by weapons that Germany delivered to Saudi Arabia at one point or another. […] If we stay silent on this, then there will be a new influx of refugees, which can't be in our interest."

Professor Henner Fürtig, director of the GIGA Institute for Middle East Studies in Hamburg, believes that Steinmeier travels south with one unusual trump card in his pocket, despite all the other international diplomatic efforts in the region from key players like the UN, US, Arab League and so forth.

"Germany does enjoy a good reputation both in Riyadh and in Tehran," Fürtig explains, before detailing the depth of existing and past economic ties. "In that regard, Germany is a tolerable mediating presence in both capitals. What's more there aren't any colonial or other such negative past issues to cloud the relationships."

As for quite how much Steinmeier might hope to achieve on the back of this political capital, Fürtig's rather more cautious. "He can at least try to get the two sides talking again," he says. "At the moment, in real terms, there's effectively zero dialogue."