BERLIN — Martin Schulz shifted into combat mode Sunday in his first speech after becoming the Social Democratic Party's candidate for chancellor.

"We are going to make the elections this year a real thrill," he said. "Our party, the SPD, has the ambition to become the strongest political force in the next election. And I have the ambition to become the next chancellor of the Federal Republic of Germany," said Schulz, speaking in front of a crowd of supporters, officials and party leaders at a packed Willy-Brandt-Haus, the party's headquarters.

It was a message that the party had been starving for. Striking these confident tones, Schulz cited the party's past, telling the crowd that former chancellors Willy Brandt, Helmut Schmidt and Gerhard Schröder "were good for Germany."

The core message went to the party rather than to the country and was a kind of "yes, we can" — in a Rheinish accent.

The party leadership (the "Vorstand") on Sunday morning chose Schulz as their candidate, a decision which, he tweeted, gave him a "crazy feeling" and made him "humble and grateful." Current party leader Sigmar Gabriel said the decision was unanimous.

The nomination followed Gabriel's announcement not to run against Chancellor Angela Merkel himself and to resign as SPD's leader.

A party congress in March is set to make Schulz's nomination official. He will resign as an MEP next week.

It will be a heavy lift for him to bring back SPD to power within the next eight months. The party polled at 20 percent before Gabriel stepped back earlier this week. Germans will go to the polls on September 24.

Germany's social democrats are not alone in a fight against political insignificance: polls forecast a defeat for the Social Democrats in the elections in the Netherlands in March. The French left, too, is divided and the Spanish Socialist Workers' party may follow their Greek comrades from The Panhellenic Socialist Movement (PASOK) into political oblivion.

"If we invest billions (of euros) to rescue banks but the stucco falls off the walls in children's schools, there's no fairness" — Martin Schulz

The candidacy of Schulz, however, may change the equation in Germany. A new poll by Germany’s ZDF television published Friday had the SPD climb up to 24 percent, while Merkel’s Christian Democrats were unchanged at 36 percent. Schulz figured high up on a list of the 10 most popular German politicians, second to another Social Democrat, future president Frank-Walter Steinmeier. The party has gotten 700 new members since Tuesday, according to secretary general Katarina Barley.

Schulz is already defining the tone and main issues of his campaign.

"Time for more justice. Time for Martin Schulz," read the first campaign billboard that was put up on the facade of the party headquarters on Sunday. It hinted at a central campaign message: that the candidate will make sure that hard-working middle-class voters aren't let behind. "I'm keen on putting the hard working people ... and their concerns at the center," Schulz said.

"It's about those people — not about the ten percent screamers, " Gabriel earlier said when introducing Schulz.

Schulz explained by example: When the local bakery pays taxes but a global coffee company doesn't, "then there's no fairness," Schulz said, in a variation on a well-known theme from previous speeches. "The fight against tax evasion will be a central issue this year," said Schulz.

"If we invest billions (of euros) to rescue banks but the stucco falls off the walls in children's schools, there's no fairness," Schulz said.

He avoided direct attacks against Merkel, limiting himself to criticizing her for a lack of vision. He went after Merkel's Bavarian sister party CSU for being disloyal and for "daily humiliations of the chancellor from within her own union." The CSU hasn't officially declared Merkel as its candidate.

He also called it an "open affront" that the CSU is "flattering and applauding" Hungarian Prime Minister Viktor Orbán who Schulz accused of taking a free ride on the EU.

"Germany is showing solidarity," he said. But if other countries such as Hungary take money from EU funds but don't want to take in refugees, "then the next federal government must connect the question of solidarity with the next EU budget framework," Schulz said.

He, who spoke for about one hour, had planned to speak "longer than Merkel but shorter than Fidel Castro," according to a party official.

Schulz countered criticism that he has no experience in German politics, given that he has been an MEP for 23 years. "Some say, 'Schulz is an EU politician and has no clue about German issues,'" he said, highlighting his years as a mayor of Würselen, a small town close to the Dutch and Belgian border.

"Every problem ends up at town halls, eventually," he said, adding that he considers such "comments about me an insult to the tens of thousands of people" in local politics. "I'm not embarrassed that I come from Würselen and that this small town ... is my home."

He pledged that "with me, there won't be any Europe-bashing" and said that when it comes to his CV — he dropped out of school and never went to university — is one he shares "with the majority of the people in this country."

A chancellor, according to Schulz, needs not only to understand people's concerns but "to have deep empathy."