Germany's opposition will force a parliamentary vote Thursday to require big companies to boost the number of women on their boards, laying down the gauntlet to Chancellor Angela Merkel five months before elections.
The draft legislation, which is expected to fail in the Bundestag lower house of parliament, has however backed Merkel into a corner and exposed a damaging rift within her conservatives.
Some 25 members had threatened to break ranks and vote in favour of the opposition motion, conservative party sources said, in a move which would have handed Merkel's rivals enough support to win a majority.
Merkel, 58, the first female leader of Europe's top economy and often cited as the world's most powerful woman, has opposed the introduction of compulsory quotas for women in the boardroom.
But her Labour Minister Ursula von der Leyen has long been a staunch backer of the move and had not made it clear whether she would toe the party's line in Thursday's ballot.
At what was described by a senior party member as an "intensive discussion", leaders of Merkel's Christian Democratic Union (CDU) agreed Monday to include in its manifesto from 2020 a 30-percent female quota in supervisory boards of large companies.
The move marks a change of course just four months after CDU members backed a flexible approach for companies to voluntarily decide on quotas for women in the boardroom at their party congress.
"Issues of equal treatment, family policy, also the (proposed) childcare payment, such things are always discussed by us in the CDU with a great deal of passion," Merkel told Thursday's Bild mass circulation daily.
"And one learns, not all women think alike," she added according to an early release of the interview.
But her spokesman told reporters Wednesday that Merkel's stance in the debate remained unchanged -- there must be more women in top business posts.
Leading CDU members had warned at their meeting that the Bundestag vote could have turned into a "train wreck" and an "unbelievable drama", according to sources among participants.
After the compromise, a dry-run vote on Tuesday revealed CDU members were now united in rejecting the opposition bid, including von der Leyen who is also a deputy leader of the centre-right CDU.
She has called the compromise "an important step forward" and, according to participants, made it clear at the meeting she would now fall into line with the party "as hard as it is for me".
However von der Leyen has come in for criticism from within her own party, with Christean Wagner telling the daily Frankfurter Allgemeine Zeitung that the minister could not afford another such incident.
"Otherwise she'll endanger the election victory of the Union," he was quoted as saying, referring to Merkel's conservatives.
Media commentators said the outcome was a defeat for Merkel, who hopes to clinch a third term in September 22 general elections, and had created bad blood within the conservatives.
"Instead of a compromise which everyone can take into the election campaign, there are bloody noses and distrust in the party," the Tagesspiegel commented.
"Because the chief (Merkel) once again didn't commit, everyone involved is in the end standing about embarrassed," it added.
Bild called it a "defeat" for the CDU leadership and Merkel but questioned whether any good could come out of it in the winning of more female votes.
"Whether this turnaround on the quota issue will now send female voters in droves to the CDU may be doubted," it said, suggesting it was about von der Leyen positioning herself for the post-Merkel era.
Merkel's junior coalition partners, the pro-business Free Democratic Party, opposes fixed quotas. FDP parliamentary group chief Rainer Bruederle expressed relief the opposition's attempt to drive a "wedge" into the coalition had failed.
The bill put forward by the Bundesrat upper house, where opposition parties hold a majority, stipulates a 40-percent quota for women in supervisory and management boards of large companies by 2023.
Women made up four percent of management board membership among the 200 biggest German companies in 2012, according to a study by the DIW economic research institute.