BERLIN (AP) — The large field of candidates vying to lead what traditionally has been Germany's main center-left party embarked Wednesday on a marathon stump tour. The outcome is expected to influence the future of Chancellor Angela Merkel's German government.

The Social Democrats are currently in a deep poll slump. They agreed only reluctantly to join the conservative Merkel's latest governing coalition last year, the third time that they have served as her junior partners.

The candidates to replace Andrea Nahles, who resigned abruptly as leader in June, traveled to the western city of Saarbruecken for the first of 23 canvassing events that will be followed by a ballot of the party's 426,000 members. A second runoff ballot will be held if no candidate wins a majority, as appears likely.

The new leadership will be installed in early December, and the party is then expected to consider whether to stay in Merkel's government, an often-cantankerous "grand coalition" of Germany's traditional big parties.

Lawmaker Karl Lauterbach, a candidate who argues that the party should leave, said at Wednesday's event that a key question in the race is "will the 'grand coalition' carry on, yes or no?"

Fifteen candidates are in contention — seven pairs bidding to lead the party as a mixed-gender tandem, plus one vying to become sole leader.

Few of them are household names.

The best-known contender is Finance Minister Olaf Scholz, who is also Merkel's vice chancellor and is partnering with Klara Geywitz, a state lawmaker.

One pair of candidates, Simone Lange and Alexander Ahrens, withdrew their bid on Wednesday.