When 40-year-old Green co-chair Annalena Baerbock was nominated as chancellor candidate in April, German media wrote of "a breath of fresh air."

The Greens rose to 28% in opinion polls in April, a spectacular increase on the 8.9% of the vote that the party got in the last general election, in 2017. The rise of the Greens coincided with a drop in support for Chancellor Angela Merkel's conservative Christian Democratic Union (CDU). Baerbock was credited for the boost, with many wondering whether she might really succeed Merkel, who is not running for reelection in September's vote. A Green chancellor? It seemed almost thinkable.

But the tide has turned. Opinion polls now put the Greens at barely 20%, while the CDU is gradually approaching 30%. Support for Baerbock individually has also gone down, putting her behind her two male competitors: Armin Laschet, from the CDU, and Olaf Scholz, from the Social Democrat SPD.

The fall has been linked to a barrage of personal attacks on Baerbock, and she has been on the defensive.

Her competitors point out Baerbock's lack of experience, as she has never held a government office.

But criticism quickly targeted her personal credibility: She was accused of minor inaccuracies in her resume, published on the Greens' website, stating that she had been a member of the German Marshall Fund, a renowned think tank, when she had never been more than a supporter. Baerbock admitted a lack of oversight and a regrettable "sloppiness" on her part.

In an interview with public broadcaster ARD, Baerbock tried to put things into perspective: "I obviously made a mistake, and I am very, very sorry. Because we should be focusing on other more important issues at this point in time," she said.

Then reports surfaced on how she paid tax on sizable Christmas bonuses only years after having received them. Baerbock was quick to again admit to annoying oversight and call it "mist" (unfortunate).

In June, Stefan Weber, a media expert and publisher from Austria, took a close look at Baerbock's new book, Jetzt: Wie wir unser Land erneuern (Now: How We Renew Our Country), and found several passages to have been lifted from other publications.

Since then, there have been piecemeal revelations from various quarters on how bits of text closely resemble various newspaper articles. Part of the book, a personal account of Baerbock's trip to Iraq, was even traced back to a DW article describing the fate of Yazidi children.

Baerbock rejected the notion of copyright infringement and plagiarism allegations, pointing out that she was "very aware of using facts from open sources." "No one writes a book alone," she said.

The Greens' reaction has been more and more thin-skinned. The party is speaking of libel and slander and says it is considering taking matters to court.

Even Baerbock's political opponents have now entered the fray, calling out the attacks on Baerbock. In an interview with the national paper Süddeutsche Zeitung on Wednesday, Interior Minister Horst Seehofer from the conservative CSU said he saw no indication of wrongdoing and called the allegations exaggerated. "This is not a thesis, there is no obligation to quote every source," he said. "It is not uncommon for passages in books to resemble parts of newspaper articles," he noted.

A touchy subject in German politics, where a number of Cabinet ministers have resigned over recent years following reports of plagiarism in their doctoral theses.

Rolf Pohl, is a sociologist and psychologist who specializes in gender studies. In the attacks on Baerbock he sees "recurring references to her looks, her family life," he told DW.

"She has become the target for a wide range of prejudice and even antisemitic slurs," Pohl said.

Social media posts spread photos of Baerbock with US investor George Soros, falsely alleging that he had made a donation to her campaign. There were posts of fake nude photos of Baerbock had allegedly posted online in her youth.

At an event in early July, hosted by women's magazine Brigitte, Baerbock said she had expected to face close scrutiny in the election campaign, "but I have seen from the beginning of my candidacy that falsehoods have been put out there deliberately, by whomever.''

The Greens seemed unprepared for the onslaught, Pohl said. Baerbock's party called the attacks on their candidate an "attempt at character assassination.''

"They seem surprisingly naive in this respect, I believe," he said. "We have known for a long time that women in prominent positions regularly become the targets of sexist attacks."

"The Greens have to take matters to court," Pohl said. "But they have to pick their battles, and make sure that their main focus is on election campaigning rather than legal procedures."

The personal attacks on Baerbock coincided with a backlash against some of her political proposals. In line with the Green party platform, she spoke out against short-haul flights and demanded a dramatic hike in petrol prices to the tune of €0.15 ($0.20) as measures to combat climate change.

Greens general secretary Michael Kellner reiterated the party's commitment to its candidate and her team. This includes party co-chair Robert Habeck, who had conceded the position as lead election candidate to Baerbock in April. Whether he might take over from her has become a recurring question.

Jens Thurau contributed to this report.

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