Three things are clear coming out of the second NDP leadership debate in Montreal. First, there's a clear sense of where the party is headed. Second, the field of leadership candidates is extremely strong. And, finally, the candidates will need to try harder to distinguish themselves.

NDP leadership candidates take part in their first debate in Ottawa, Sunday March 12, 2017. (Photo: Justin Tang/Canadian Press)

This is in strong contrast to 2012, when last the NDP had to choose a leader. The task of replacing Jack Layton in 2012 forced the party to make many tough decisions, foremost over whether to bring the party closer to the political centre under Thomas Mulcair. But the current race has four candidates all of whom push a strong social democrat vision. They each refer frequently and favourably to Jack Layton's legacy, but rarely to Thomas Mulcair's. Regardless of which candidate prevails in the end, the party will be pushing a solidly progressive vision.

The 2012 race also included contenders who had limited political experience, and some who had never held public office. The current candidates are all sitting MPs, veterans of multiple elections, and comfortable and articulate debating the full range of issues. As Chantal Hébert affirmed after the bi-lingual Montreal debate last week, it's easy to imagine any one of the four leading the party into the next election.

But this is the real challenge: finding the candidate who has the political skill to be competitive in the next general election. The NDP leader will have to be smooth, photogenic and charismatic enough to compete with Liberal Leader Justin Trudeau. This same leader will have to be able to get down and dirty to fend off the low blows from whoever wins the Conservative race. (And if O'Leary wins, you can be sure the next election is going to be the political equivalent of professional wrestling.) Finally, the new NDP leader will have to be able to score big in progressively minded Quebec despite a rejuvenated Bloc Quebecois under Martine Ouellet.

The future NDP leader will need to demonstrate an uncanny ability to bridge constituencies like never before.

Unfortunately, the current NDP leadership debates haven't been sufficiently combative enough to discern the traits necessary to call out the most effective leader. The two debates have had moderators who were far too friendly, and left-leaning themes which -- rather than distinguishing the candidates from one another -- only tended to make them appear more similar.

It may well be that the four candidates have very similar visions, but if that's the case, then the debates need to help viewers discern who can best execute on this vision. The NDP faces huge challenges as it looks forward to the next federal election. The party faces a large debt and perennial struggles to raise money. Candidates need to detail their plan to address these financing struggles, identify new sources of funding, and talk to their successes in addressing fundraising challenges of the past.

Each of the four candidates suggested the party needed to reconnect with Canada's grassroots social movements: environmental groups, indigenous groups, student groups and the like. NDP membership numbers are down, and the competing political noise from other parties is deafening. Candidates need to articulate concrete ideas about how each will develop the grassroots base, citing successes from their own past experiences.