The NDP’s long-held mantra of being prepared to debate anybody, any time, anywhere is slowly being upended by the first public opinion surveys of the 2015 campaign that show the party’s slim, front-runner status is holding.

Going into the first face-to-face leaders encounter on Thursday, a trio of political experts say polls showing a tight two-way race with the governing Conservatives are making New Democrats more cautious.

That has manifested itself in Tom Mulcair’s refusal to take questions at the campaign launch on Sunday and his recent demand that Stephen Harper be present for all debates — or he won’t participate.

A snapshot of public opinion by the Forum Research, taken Sunday as the campaign opened, suggested the NDP was trending upwards and commanded 39 per cent popular support, something that could put them close to solid minority government territory.

According to the survey of 1,399 respondents, the governing Conservatives were pegged at 28 per cent, down from the previous survey; the Liberals were unchanged at 25 per cent; the Bloc Quebecois garnered five per cent nationally; the Green Party three per cent.

Another survey, the Nanos Power Index, which measures four-week rolling average numbers suggests the Conservatives were closing the gap with the NDP in a slow, steady march throughout July.

Since the spring, polls have shown a surge in NDP support that some pundits initially dismissed as an Alberta election-related blip that wouldn’t hold into the campaign.

“Now that he is at least competitive with the Conservatives and certainly ahead of the Liberals, Mulcair figures why does he have to go into a debate with Trudeau or Elizabeth May,” said political scientist and polling expert Barry Kay, of Wilfrid Laurier University in Waterloo, Ont.

The NDP initially agreed to attend a debate held by a consortium of big broadcasters. The Conservatives had previously declined to participate, saying they had received too many invitations.

Kay said that decision might come back to haunt the Conservatives as the polls show they need to reclaim ground beyond their bedrock support which has hovered in the range of 30 per cent.

“One would think debates are a great opportunity for the Conservatives to show their stuff and try to push towards the 170 seats they need from where they are now, which is 125; somewhere in that range when you look at the projections,” he said.

“I don’t understand the Conservative strategy. Maybe they think their ads will be the path to victory and they don’t need debates. They’re having debates in basically invisible places.”

The first encounter is hosted by Maclean’s magazine in Toronto. It will air on the City-TV network, Omni stations and CPAC, as well as a chain of AM radio stations. The event will also be live streamed across various Rogers-owned websites, on Facebook and YouTube.

The Globe and Mail is organizing a debate on Sept. 17, the University of Toronto’s Munk Debates is planning a leader’s exchange on foreign policy, and French network TVA will play host to a televised debate covering general topics on Oct. 5.

The broadcast consortium says it offers the greatest possible platform, with more than 10 million viewers tuned in to the English-language debate, and four million to the French version, in 2011.

Lorne Bozinoff, president of Forum Research, said the NDP are clearly not going to want to rock the boat and low-key debates could work in their favour, even though Mulcair is seen as a skillful debater.

“The NDP have been on a roll, so, if it’s not broke, don’t fiddle with it,” he said.

In terms of polling numbers, Justin Trudeau is the one with the most to gain with a good debate performance, said University of Toronto associate professor Nelson Wiseman.

“I think Trudeau has performed well in the first few days,” Wiseman said. “I think he recognizes what’s at stake here. He’s scripted, but he’s not saying the stupid things he did in the past. He’s saying what he’s saying with some panache and I think he believes what he’s saying.”

He may have looked good at the outset, but Wiseman said he wonders how Trudeau will fare in the bear pit with Harper and Mulcair, if he’s attacked at all. Being ignored would be the worst possible outcome for the Liberals, something that would resonate in media stories, even if Thursday’s actual debate audience is made up of mostly political junkies.