After British MPs voted on Wednesday to approve joining the French bombing campaign against Isis, and with a crushing majority in parliament for Chancellor Angela Merkel's coalition government, German approval for a Syria mission looks all but certain.
But there are fundamental questions open that critics say the government has failed to answer satisfactorily.
These are some of the most important.
1. What forces would Germany send? What will they do?
Germany currently plans to send Tornado jets on reconnaissance flights over Syria, a frigate to defend French aircraft carrier Charles de Gaulle, and an air refuelling tanker to support other nations' planes.
In total, around 1,200 soldiers should be involved if the deployment goes ahead.
Defence Minister Ursula von der Leyen has dismissed fears that the Tornados might not be in a fit state to fly, with half the fleet out of action, saying that only four to six of the planes will be enough.
A Lutfwaffe (German air force) Tornado landing at Masar-i-Scharif, Afghanistan. Photo: DPA
But critics have argued that this plan will do little to help the fight against Isis.
“American drones and planes are already flying recon missions over Isis territory daily,” Bild online editor Julian Reichelt wrote on Tuesday.
“The Americans already have a list with hundreds of targets… most of them can't be attacked in any case because they're in residential areas.
“MPs must clarify why they want to risk the lives of German pilots to add further targets that can't be attacked to this list.”
Others have pointed out that compared with live video feeds from drones, hours-old reconnaissance photos from the German Tornados are likely to be of little use even if they show targets that could be attacked.
Guerilla-style Isis fighters are likely to have moved on long before an airstrike could be authorised on targets identified by the Tornados.
German navy frigate Augsburg. Photo: Wikimedia Commons
Meanwhile, the Augsburg frigate that will join Charles de Gaulle is a submarine defence ship, defence blog Augen Geradeaus [Eyes Front] notes – hardly likely to be much in demand in the battle against Isis.
2. Is there public support for military action?
A YouGov poll released earlier this week found that 45 percent of people supported military action against Isis while 39 percent were against.
But the public are also worried that joining the anti-Isis coalition will make Germany a target for terrorists, with 71 percent convinced the threat is already high and just 18 percent unconcerned about a backlash.
3. How long will the mission last? What's the long-term strategy?
The government is only asking for permission to commit to the anti-Isis mission for 12 months – the normal length of a military mandate for German forces.
But that's very unlikely to be long enough to see off Isis.
In a Bundestag (German parliament) debate on Wednesday, Defence Minister Ursula von der Leyen acknowledged that “the length of the deployment will be very strongly dependent on how successful the decisive, political process is.”
Frank-Walter Steinmeier (l) and Ursula von der Leyen in the Bundestag on Wedesday. Photo: DPA
She means the tentative peace talks that have begun in Vienna, which Foreign Minister Frank-Walter Steinmeier has called the best hope of ultimately defeating Isis and ending the civil war in Syria.
But the Foreign Minister added in comments backing the proposed military action in the Bundestag debate on Tuesday that “shutting ourselves away, lights out, shutters down, if terrorists are marching through the streets” could not be Germany's response.
André Wüster, chairman of the Army Union, warned that the fight against Isis could last up to 10 years in comments earlier this week.
4. Will Germany be working with Assad and Putin?
In recent days, France has been showing signs of cosying up to Russian President Vladimir Putin – who just weeks ago remained persona non grata in Europe over his illegal annexation of the Crimea from Ukraine.
Russian forces have already been fighting in Syria for some time – although there have been accusations that their bombs are falling on rebels battling brutal President Bashar al-Assad, not Isis.
President Bashar al-Assad of Syria (l) with Vladimir Putin at a meeting in Moscow in October 2015. Photo :DPA
Defence Minister von der Leyen has insisted that Germany's involvement won't help Assad, who has indiscriminately bombed large swathes of his country's cities with so-called “barrel bombs” as well as using chemical weapons.
“There will be no future with Assad, and there will be no working with troops under his command,” she told Deutschlandfunk radio on Tuesday. “We won't work together with leaders with blood clinging to their hands.”
But Green Party leader in the Bundestag Katrin Göring-Eckhart has accused von der Leyen of a “zigzag course” over the question of co-operating with Assad – as well as with Qatar and Saudi Arabia, the two countries providing “the ideological material for this [Isis] terrorism.”
5. Is it legal for Germany to join the war?
The German Constitution imposes strict limits on when military forces can be used.
The federal government argues that Article 24, Clause 2 of the Constitution, which says that the government can join a “system of mutual collective security for the preservation of peace”, is justification enough to join France as its steps up the war against Isis.
That's because in the wake of the Paris attacks, France invoked the never-before-used article 42.7 of the European Union's Treaty of Lisbon, which states that “If a Member State is the victim of armed aggression on its territory, the other Member States shall have towards it an obligation of aid and assistance by all the means in their power.”
President Francois Hollande of France speaking in front of French and EU flags at a memorial ceremony for the victims of the Paris terror attacks. Photo: DPA
Article 51 of the Charter of the United Nations also states that nations have the “inherent right of individual or collective self-defence if an armed attack occurs… until the Security Council has taken measures necessary to maintain international peace and security”.
And UN Security Council resolution 2249 calls Isis “a global and unprecedented threat to international peace and security” and “calls upon Member States that have the capacity to do so to take all necessary measures… to redouble and coordinate their efforts to prevent and suppress terrorist acts committed” by Isis, “and to eradicate the safe haven they have established over significant parts of Iraq and Syria”.
A meeting of the United Nations Security Council in New York. Photo: DPA
But writing at Verfassungsblog [Constitution Blog], critic Sophia Müller argues that resolution 2249 does not specify the “necessary measures” to satisfy the conditions in Article 51 of the UN Charter.
Müller also questions whether the Paris attacks were serious enough to fit the definition of an “armed attack” on the level a state might carry out.
In the past, only the September 11, 2001 attacks on the USA, which claimed many more lives and caused vast amounts of damage, have been seen as serious enough to meet that standard.
Müller also argues that France should have invoked article 222 of the Treaty of Rome – which deals specifically with terrorist attacks and does not justify military interventions abroad – rather than article 42.7 of the Treaty of Lisbon.
“The legal foundation of the decision for a military deployment does not hold up in any aspect,” Müller concludes. “It would be an illegal mandate” which the opposition could readily challenge in the Constitutional Court.
Even one MP from Chancellor Angela Merkel's party called the legal basis for a Syria intervention “thin ice” in comments to Spiegel Online last week – but added that “it should hold”.