Germany's Social Democrats, in a reversal, have renewed the possibility of an alliance with Chancellor Angela Merkel's CDU. This would have implications beyond Germany's borders.

The three emotions of the moment:

• Fatigue: Even if the CDU and Social Democrats (SPD) do hitch up, most Germans won't like it. Only 39 percent of them favor a renewed "Grand Coalition" of this kind. Moreover, the SPD — which is at its weakest since 1949 — will be at pains to show voters that it's not just a second-fiddle to Merkel. This means that unwieldy intra-coalition politics will hobble the Merkel's ability to act.
• Anger: The far-right Alternative for Germany (AfD) party now holds 92 seats in parliament. And while it's in no position to be a kingmaker, the weakness of Merkel's coalition could increase the party's anti-establishment appeal, compounding her troubles.
• Despair: French President Emmanuel Macron's bold initiative to reform and revitalize Europe requires a strong, willing Germany. Absent that, it will be harder for Europe to cope with an increasingly assertive brand of populist nationalism.

Bottom line: Merkel will enter her fourth term significantly weakened, and that's bad news for Germany and for Europe.

Go deeper: Right-wing populists surge in Germany

Sign up for Eurasia Group Media's Signal newsletter.