Outgoing NDP Leader Tom Mulcair is steering clear of commenting on his party's leadership race, but says the NDP should strive to influence policy while keeping its eye on one goal: governing.

"I do think that the main purpose to be in politics is to govern. You have ideas. You have ideologies, one would hope that they'd be pure, and you want those to actually become reality for Canadian society," he told Terry Mileswki on CBC Radio's The House.

"So those will be economic, they'll be environmental, they'll be social and I think that the only reason to go through all of this exercise is to make sure that you can, one day, attract enough voters to agree with you."

In April Mulcair lost a leadership review vote in a stunning turn of events at the party's convention. A convention that also saw the rise of the Leap Manifesto, a document that calls for dramatic change within the party including a transition away from fossil fuels, a rejection of new pipelines and an upending of the capitalist system on which the economy is based.

Now the NDP is now faced with two questions, not just who should replace Mulcair as leader, but what the soul of the party should look like.

Some members believe the party should stand up for left-wing, socialist principles — others want a realignment to the centre in the hopes of one day forming a government.

'Not' somebody else's conscience

During Sunday's debate, the four candidates vying to replace Mulcair, so far, pitched different versions of the party.

Niki Ashton, calling herself a "democratic socialist" and an "intersectional eco-feminist," ventured that the NDP "played it too safe" and let the Liberals "out-left" them.

Peter Julian talked about a need for "bold" policies, while Charlie Angus promised that, as leader, he would bring "fun" back to the NDP.

The four declared candidates for the NDP leadership so far, from left: Niki Ashton, Charlie Angus, Guy Caron and Peter Julian. (Canadian Press)

Economist Guy Caron argued that the party needed to reconnect with Canadians outside the House of Commons.

Mulcair argued many of the policies that pushed the Liberals to their majority win, were actually stolen from the NDP's playbook, such as electoral reform and environmental oversight on pipelines.

"A lot of people are looking at the NDP now, not as somebody else's conscience, because you can't be the conscience of someone who doesn't have one, but as being a party that is capable of governing this country with only one priority: reducing inequalities in our society and making things better for future generations," he said.

"I still love the NDP."