New Democrat Leader Jagmeet Singh could face some tough questions as the ink dries on a newly announced deal that would see his party support the Liberal minority government for the next three years.

"They don't have any more power by this at all," said Lori Turnbull, a professor of political science at Dalhousie University.

Details of the confidence and supply agreement the NDP reached with the Liberals were kept a closely guarded secret by a small circle of people around the leaders of both parties until Monday evening, when members of Parliament from both parties were let in on the plans.

And while Singh said his caucus supports the deal, the regular weekly caucus meeting on Wednesday will be a chance for NDP MPs to further discuss this significant shift in party focus.

The deal says NDP MPs will side with the Liberals on key votes until 2025 — meaning they won’t bring down the government over the coming budget, for example, which is expected to be released in the next few weeks.

In return, the Liberals have promised movement on some key NDP issues. But the document released by the Prime Minister’s Office on Tuesday is short on details about how that will happen.

Turnbull said while deals like this tend to be uncommon, it's fully within normal parliamentary practice for parties to work together, especially in a minority situation.

Where it could become problematic, she said, is if the Liberals use it to truncate debate on important bills. It's too early to know whether that's where things are headed.

"There's an obvious incentive here to take everything and jam it into an omnibus budget bill so that everything has to go through," she said.

Political scientist Lori Turnbull says confidence and supply deal is unnecessary. #CDNPoli #Liberals #NDP

"There is a loss for accountability if that's where this ends up."

Two of the major priorities — dental care and pharmacare — come with significant price tags and will require the co-operation of the provinces.

In question period in the House of Commons on Tuesday, interim Conservative leader Candice Bergen called the Liberal government’s previous spending “out-of-control,” and questioned how much the new promises to the NDP will cost.

“Now Canadians are going to be living with a new NDP-Liberal government and that price tag has just skyrocketed,” Bergen said.

A dental-care program for lower-income Canadians is to begin this year by providing services to children under 12, with full implementation by 2025. A cost estimate hasn't been provided.

Singh promised to implement government-subsidized dental care in both the 2019 and 2021 elections. The NDP estimated in September that complete dental care coverage would cost $1.5 billion in the first year and just under $1 billion a year later.

The parties also say they will “continue progress toward a universal national pharmacare program” by passing legislation before the end of 2023.

A 2019 expert panel report estimated pharmacare would cost the government $3.5 billion a year initially, rising to $15.3 billion by year five.

B.C. NDP MP Jenny Kwan said many of her colleagues are excited about making those two programs happen.

"If we were in government, we would be able to do more, but this is a minority government and so this is about compromising, getting as much as you can," she said.

Given that the two parties are closely aligned on many of these stated priorities already, Turnbull questioned why a deal was even necessary.

"To me, this is a bunch of political theatre," she said.

Prime Minister Justin Trudeau said the agreement ensures government predictability, citing global and economic instability caused by Russia's invasion of Ukraine.

Conrad Winn, a political-science professor at Carleton University, said the world military situation has shifted dramatically in recent years. There have been calls for the Liberals to increase military spending, an issue that could drive a wedge between them and the NDP.

“I think it's relevant to the stability of Justin Trudeau’s job as prime minister, but it's irrelevant to Canada's stability,” Winn said.

“Because on the central issue, military preparedness, the NDP and the Liberals could not be more far apart.”

Trudeau said that issues on which the two parties do not agree will be managed on a case-by-case basis, and that the Liberals could still get support from other parties in some votes.

Meanwhile, the Liberal leader won't be in his party's caucus meeting Wednesday. Trudeau is instead in Brussels to meet with EU, NATO and G7 leaders about the war in Ukraine.

This report by The Canadian Press was first published March 23, 2022.