German authorities identified the attacker who killed nine people and injured 27 others in Munich on July 22 as an 18-year-old man of Iranian descent who was born and raised in Germany. The victims included three Kosovo Albanians, three Turkish citizens and a Greek national. Authorities have searched his apartment but have so far not found any connections with the Islamic State. The perpetrator had earlier sought help for mental health issues. This shooting comes soon after a July 19 ax attack on a train in Wuerzburg. And it was the third attack in Europe in a week, following the July 15 incident in Nice. While the perpetrators, their methods and their motivations were starkly different in all three cases, these incidents will trouble the temporary political calm that has set in over the role of migrants in Germany. This will lead only to more problems for the government of Chancellor Angela Merkel.

After serious political backlash, the political controversy that followed the migrant crisis seemed to have partly subsided. During the second half of 2015, Merkel's decision to accept asylum seekers fleeing the conflict in Syria led to a massive increase in refugees in the country. Though the German population initially welcomed Merkel's decision, over time many expressed anxiety over the social, economic and political impact of receiving hundreds of thousands of migrants. This hurt the popularity of the German government and led to tension within Merkel's Christian Democratic Union. It also caused difficulty with the Christian Democratic Union's Bavarian sister party, the Christian Social Union. The migrant crisis led to a surge in popularity for the anti-immigration Alternative for Germany party.

Merkel's reaction was to toughen Germany's asylum regulations, accept border controls along the Balkan migration route and make a deal with Turkey to limit the number of people reaching the European Union. The EU-Turkey agreement was controversial, but it staunched the flow of migrants after it went into force in late March. As the migration crisis eased, Merkel's popularity started to improve again. 

But this week's attacks will fuel Merkel's opponents. The Wuerzburg attacker was a teenage refugee, a fact that will be brought up by political forces to argue that migrants are a threat to Germany. And German authorities appear to have bungled the case: The attacker was registered as an Afghan refugee, but authorities admit he may have been from Pakistan. This has brought into question their ability to properly register and monitor migrants. Though the Munich shooter was not a refugee, his Iranian origin will do little to appease anti-Muslim sentiments in Germany. In 2014 and 2015, the anti-Muslim Pegida group staged large demonstrations in Dresden and other German cities. The group announced in early July that it plans to become a political party and support Alternative for Germany. German authorities have recorded 1,029 attacks against asylum shelters in 2015, up from 199 in 2014. The first quarter of 2016 saw almost 300 attacks against shelters. Unfortunately, lone-wolf attacks such as those in Munich, Nice and Wuerzburg are likely to continue in Europe and elsewhere. And they will continue to have social and political repercussions.

The German government's largely successful scheme to stem the flow of migrants is also in jeopardy. Turkey's agreements to screen asylum seekers hinged on Ankara's demands for EU funding, membership negotiations and visa liberalization. But a failed Turkish coup has led to a crackdown on the opposition, provoking criticism from EU members. Berlin now finds itself in the awkward position of warning about the rule of law in Turkey and saying that the migration agreement has to be respected. The European Parliament and EU members will debate the issue again in early September, and the German government will find it hard to convince them to preserve the agreement.

German regional elections on Sept. 4 in Mecklenburg-Vorpommern and on Sept. 18 in Berlin will be an indicator of the popularity of the ruling center-right and center-left coalition and of Alternative for Germany. If Merkel's Christian Democratic Union performs poorly, the chancellor will be under growing pressure to toughen her position on migrants. A poor performance by her party would also affect Germany's behavior on issues well beyond immigration, since the country already disagrees with its southern peers such as France and Italy on how to manage the eurozone. And with attacks occurring across Europe, incentives will increase for EU members to tighten cooperation on security issues, although the establishment of a security union will remain elusive.