For some, German Chancellor Angela Merkel has become both the economic and moral leader of Europe. From tackling the eurozone's debt crisis to countering Russian ambitions to bucking the tide of populism to welcome a million refugees into her country last year, Merkel has been lauded for her quiet but principled pragmatism in the face of the most complicated national and international challenges.

But after Monday's terror attack at a Christmas market in Berlin that left 12 people dead, her already fragile sway over domestic public opinion might finally begin to slip away before crucial national elections next year.

German police named Anis Amri, a 24-year-old Tunisian, as the No. 1 suspect in the attack, where a truck plowed into a crowded market. According to Deutsche Welle, there is growing anger in Germany over the authorities' failure to prevent the attack. Amri, who came to Germany in July 2015 had been under investigation for months, was on a U.S. no-fly list and managed to escape deportation after his asylum application was rejected.

"Public Enemy No. 1" — Morgenposten, Dec. 22, 2016

Even though Amri wasn't apparently among the waves of refugees that have flooded Germany, politicians have still sought to capitalize on the terror attack by blaming Merkel. Nigel Farage, the former leader of the UK Independence Party who had campaigned for Britain's exit from the EU, wrote on Twitter: "Terrible news from Berlin but no surprise. Events like these will be the Merkel legacy."

As Germans fear more terror attacks on their soil, and populists relentlessly feed on public fear, it's hard to overestimate the challenges Merkel faces as she seeks a fourth term in the fall of 2017. Europe will be watching.

See more from World Affairs here