The popular Widmer-Schlumpf announced her resignation for personal reasons ten days after her Conservative Democrat party lost ground in Switzerland's October 18th general election.
The finance minister has sat in the seven-member cabinet since 2007 when she was elected to hold the second seat of her then party, the right-wing Swiss People's Party (SVP), over its top choice, maverick figurehead Christoph Blocher.
Kicked out of the SVP, Widmer-Schlumpf nevertheless held onto her seat and joined the Conservative Democrats.
She went on to enter the seven-seat government with her new party thus depriving the right-wing SVP of its cherished second seat in the cabinet.
But her resignation could now allow the SVP, which enjoyed a record performance in the elections, to regain that second seat when the joint assembly votes to elect the government on December 9th.
The seven posts are traditionally shared among the major parties on the right and left sides of the political spectrum. Given the SVP is now Switzerland's largest party – it won 65 seats in the lower house in recent elections – it has a strong claim on the seventh cabinet seat.
On Thursday the SVP - known as the UDC in French-speaking Switzerland - expressed its intention to that effect by tweeting it was “ready to assume its extra responsibilities”.
L'UDC est prête à prendre des responsabilités supplémentaires https://t.co/JobzzZ7QnN— UDC Suisse (@UDCch) October 28, 2015
Widmer-Schlumpf's departure is “an early Christmas present” for the SVP, according to the Tribune de Genève, which quoted the party's president Toni Brunner as saying “This is a chance to be represented by a federal councillor defending a harder line on asylum and Europe.”
It's a situation that dismays the political left.
“To win, the SVP doesn't even need to present one of its more moderate members. We are moving towards difficult times,” Socialist national councillor Roger Nordmann told the Tribune.
To fend off the challenge from the SVP, the hopes of the political left rest on the centre parties, who could unite to support an alternative.
“The ball is now in the camp of the centre parties, who have the right to claim this seat. It's a solution that we support,” said Adele Thorens Goumaz, co-president of the Greens.
However the chance of that happening is slim, writes the Tribune.
In a statement, the centre Christian Democrats (CVP) party said it “accepted the SVP's claim on the subject of a second seat”.
The vice-president of the Swiss Socialist Party Géraldine Savary bemoaned the lack of cohesion among the centre parties.
“A second seat in the centre would be legitimate, but the centre parties are not demonstrating any willingness in that regard. By default, the seat will return therefore the SVP.”
But a second SVP seat would not come without conditions, according to the Tribune – namely, that any candidate should respect bilateral agreements with Europe and the European convention on human rights.
For some, that's incompatible with the right-wing SVP, which advocates tighter laws on asylum and proposed the successful 2014 referendum on limiting immigration to Switzerland, an initiative which countered the country's bilateral agreements with the EU.
“How can we save these agreements if we elect a second hardline SVP minister?” said Nordmann.
“The [SVP] party can no longer behave as it has done to date. I won't compromise on that,” said Dominique de Buman of the CVP.
Despite the SVP's gains on October 18th, a recent survey by the Swiss Broadcasting Corporation found that most voters polled didn't want the right-wing party to gain more power in the cabinet.
The other incumbent cabinet members are expected to retain their seats on December 9th.