Dutch ruling party leaders gathered in The Hague on Tuesday night for emergency talks after the Senate unexpectedly voted down health reforms.

Health Minister Edith Schippers, who is tipped as a potential successor to Prime Minister Mark Rutte as liberal party leader, said she was disappointed the upper chamber had rejected her proposal to allow health insurers to limit customers’ hospital choices.

The measure was meant to raise efficiency and save the government €1 billion in health spending annually.

Three Labor Party senators voted against the proposal, triggering a crisis in the coalition.

Senate drama

The ruling parties do not command a majority in the Senate.

Usually a sleepy constitutional body that can do little more than send legislation back to the lower house, the narrow balance of power there has encouraged opposition parties to try to drive a wedge between the left- and right-wing parties that formed a government in 2012.

The ruling parties had secured the support of the liberal Democrats and two small Christian parties for their health reforms, giving them a one-seat majority.

Other opposition parties oppose Schipper’s reforms, meaning they cannot pass without the support of the full Labor Party.

Parties down in the polls

The liberals, who support further liberalization in health care, can ill afford to give in. Their many compromises with Labor have already cost them popularity. The latest Ipsos poll shows the liberal party losing thirteen of its 41 seats.

Labor does even worse. Ipsos gives the social democrats fifteen seats out of 150. Peil.nl, another survey, has them at eleven.

The bad poll figures have undermined Labor Party leader Diederik Samsom’s authority. Dutch media speculate he will be replaced by the social affairs minister, Lodewijk Asscher, before the next election.

Tuesday’s Senate rebellion further undermines Samsom’s leadership.

Senate elections are due in March. The three Labor dissidents are expected to retire then. The coalition could postpone its reforms, but that would blow a €1 billion hole in this year’s budget.