Jack Layton’s “proposition, not opposition” approach to politics gained him plenty of points in the election campaign, but will be put to a harsh test as he leads the Opposition against a Conservative majority government.

“I’ve always favoured proposition over opposition. But we will oppose the government when it’s off track,” Layton said in his victory speech after winning more seats than ever before and setting himself as leader of the official Opposition.

“We’ll support positive suggestions that we’ll bring forward and support the government when it’s making progress,” Layton vowed.

But the animosity between Layton’s NDP and the Stephen Harper Conservatives runs deep.

Even during the long stretch when the NDP was the fourth party in Parliament, Layton had his hands full keeping the anti-Harper sentiment in his party under wraps.

Layton always needed to lace his diplomacy with enough negative rhetoric to keep the wolves at bay, even as his conciliatory, roll-up-your-sleeves slogan to “fix Ottawa” has been his rallying cry.

Now, with a host of untested MPs elected on an anti-establishment surge with its roots in a fluid Quebec electorate, Layton may be tempted to revive the acerbic tone of Parliaments past — the very tone he ran against.

He’ll also have to reconcile the bold promises he made to appeal to Quebec voters with the centralizing philosophy that has historically underpinned the NDP.

More than half of Layton’s new caucus is from Quebec. Most of the new MPs are relatively unknown, although three or four of the 50-some new members have high profiles. But in his victory speech, Layton did not single out Quebec issues or dwell on his commitment to bring Quebec into the constitution in his victory speech.

Layton is driven to win, and he wants to do what it takes to make his policies a reality. But he is also driven to decimate the Liberals, said political scientist Peter Graefe of McMaster University in Hamilton.

“The temptation is to run a pretty strong, negative opposition,” Graefe.

That’s a sentiment many longtime New Democrats share, but may not have in common with voters who are test-driving the party for the first time.

The 61-year-old Layton personified the campaign from beginning to end. Recovering from hip surgery, he started out with a heavy, painful limp and finished brandishing his now-trademark cane in the air in victory.

By all accounts, Layton led a campaign that was successful beyond anyone’s wildest dreams — partly due to strategy, partly due to luck as his opponents faltered and his smile caught the eye of the public.

After finding his sea legs in previous campaigns and building up the party’s backroom expertise and fundraising over his eight years in Ottawa, Layton and his team designed a tightly scripted and narrowly focused campaign.

They had seen their membership and their seat count climb slowly and steadily over the last eight years and felt their base was solid enough to reach out.

Assuming their incumbents were mainly safe, they zeroed in on ridings where they placed second in 2008. They also started moving beyond their traditional target of women, unions, and the working class.

Inspired by the Darrell Dexter victory in Nova Scotia in 2009, the party held its national convention in Halifax and emerged determined to plot a path to victory — putting philosophy second.

The convention and Dexter himself, convinced the federal party to focus on pocketbook issues and a small set of practical positions — rather than taking an ideological stand on everything.

“That convention was definitely a turning point,” said one insider. “It became about a very tightly simplified message. It’s about focus. It’s about selecting messages that connect.”

In contrast to the resources thrown at the minute-by-minute advance planning for the campaign, planning for the post-campaign manoeuvring has been minimal, officials say — partly because they’ve been taken by surprise and partly because they don’t want to raise expectations.

“Plans for different options have been thought through — going back almost a year,” Layton said in a recent interview.

“The essence of that plan is to phone all the other leaders and say this what we’d like to accomplish.”

But since no one had a clear grasp of who would be in the new NDP caucus, or how big the Quebec contingent would be, the party’s most likely front bench has been in flux.

Newly-elected Robert Chisholm, who revived the provincial NDP in Nova Scotia and prepared the ground for Dexter’s victory, will no doubt play a large role in advising Layton on steps forward.

Two new members from Quebec — former union chief Nycole Turmel and former Liberal-turned-NDP MP Francoise Boivin — are also expected to play large roles.

Layton is to hold a news conference on Tuesday, but then wants to spend a couple of days at home, regrouping with his family.

That’s not a sign that he’s going into seclusion. His family includes his wife, Olivia Chow, who is one of the federal NDP’s top strategists. They live and breathe politics.