ESSEN, Germany — The mood among the comrades was restive.

Two dozen members of the local chapter of the Social Democratic Party patiently sat through the order of the day — public toilets, the closure of a slaughterhouse — until discussion finally turned to agenda item No. 8.

It was the question all were waiting for: Should their proud but ailing party join Chancellor Angela Merkel in another coalition government — despite having categorically ruled it out for most of last year?

“Comrades,” Matthias Vollstedt, the jovial bow-tie-wearing leader of the local party chapter, asked the eclectic group of workers, students, civil servants and pensioners, age 22 to 82, “is there anyone in the room who actually wants this?”

Not a single hand went up.

Therein lies a potentially major stumbling block not only for Ms. Merkel, but for all of Europe, which has been waiting for Germany to form a government for three and a half months since its inconclusive September election.