OTTAWA—New Democrats and their like-minded friends must be more than anti-Conservative if they want to lead Canada in a new direction, says former party leader Ed Broadbent.

“We need to defeat bad Conservative ideas, but we also need to ensure that it is progressive ideas and policies that take their place,” Broadbent said in an advance copy of a speech he will deliver to open Progress Summit 2015.

The two-day conference organized by the Broadbent Institute, the left-leaning think-tank established in 2011 to promote social democratic ideas and policies, will feature panels and speeches on topics such as income inequality, harnessing the power of unions, food security, climate change and relations with Aboriginal Peoples.

“Simply preventing further erosion is not good enough. We need to move our country to a new and better place. Canadians deserve better than a new federal government that, while perhaps being a bit more polite, continues to make inadequate decisions,” Broadbent says in the speech.

The underlying message in the speech is that if Canadians want to see real change, returning the Liberals to power is not enough.

“Take environmental policy, for instance. Yes, it’s true that the Harper government has burned any semblance of proper federal regulation to the ground,” Broadbent charges.

“The reality is, though, that the environmental legislation that Mr. Harper destroyed wasn’t that great to begin with. For years prior to Mr. Harper’s election, Canada was bottom of the barrel in terms of international rankings of environmental performance.”

The criticism of the Liberals becomes more obvious when Broadbent turns his attention to the proposed federal anti-terrorism legislation known as Bill C-51.

The Liberals proposed amendments to the legislation Thursday, but have also said that they would let it pass through the House of Commons even if their suggested changes are rejected, promising instead to introduce their own measures if they win the election.

“I worked hard with Pierre Trudeau between 1980 and 1982 to create what is possibly the best Charter of Rights in the world,” Broadbent says in the speech.

“I never thought I’d see the day his party would back away from its defence. C-51 is flawed. C-51 is dangerous. C-51 must be defeated by Parliament.”

The NDP has said it would not support the bill in its current form.