On Tuesday, Prime Minister Justin Trudeau announced that Canada’s ruling Liberal Party and opposition New Democratic Party (NDP) had reached an unexpected agreement to keep the minority government in power until 2025.

Governments with a minority of seats in parliament, such as the one Trudeau now leads, typically last two years, but this unusual agreement could allow it to serve out the entire four-year term, according to Trudeau.

“What this means is that, even in this uncertain period, the government can function with predictability and stability, present and implement budgets, and get things done for Canadians,” Trudeau said.

The two parties published a list of priorities they had agreed upon.

The Liberals agreed to back a national dental-care program for low-income Canadians and to move forward on a national prescription-drug coverage program, both cornerstone campaign pledges for the NDP.

The Liberals and New Democrats also said they would develop a plan to phase out financing for the fossil fuel sector, starting in 2022.

Trudeau, who has been in power since 2015, will be able to deliver on his main campaign promises, like fighting climate change or addressing a national housing shortage.

“We have a document … that will be used to analyze and verify the government’s actions,” New Democrat leader Jagmeet Singh told reporters. “We will use our power to help people.”

Singh six months ago ruled out a deal to keep the minority Liberal government in power, but added he was willing to support Trudeau on a case-by-case basis.

Opposition Conservative leader Candice Bergen said Canadians had been “hoodwinked” and “deceived” by Trudeau.

“This is nothing more than a Justin Trudeau power grab,” Bergen said, adding that it would lead to “the decimation” of the country’s oil and gas sector. Bloc Quebecois leader Yves-Francois Blanchet called the deal a “false majority” that betrayed last year’s vote.

In the House of Commons, the deal will give the government 184 total votes. A majority is 170 and the Liberals have 159 by themselves. Singh said the deal would stay in place as long as the Liberals lived up to their commitments.

Trudeau has failed to gain a majority of seats in parliament in the past two elections. So the left-leaning NDP has backed Trudeau in key votes since 2019, but this agreement formalizes future support.

While a so-called “supply and confidence agreement” is not unheard of in Canadian politics, it is unprecedented to have such an agreement in writing at the federal level.

In 2004, Conservative leader Stephen Harper sought to unite the opposition to bring down Paul Martin’s Liberal government, but failed. However in 2017 an NDP government in British Columbia functioned with the informal support of the Green Party until 2020.

The deal does not create a formal coalition and the New Democrats will not be part of Trudeau’s cabinet.