Some people say Stephen Harper's real goal as prime minister is to make Conservatives Canada's Natural Governing Party in the 21st century. If so, I think he's going about it the wrong way.To understand why, first, let's remind ourselves where the idea comes from. The Liberals were the NGP of the 20th century because they occupied the space between conservatism and social democracy, which allowed them to move left or right, as circumstances required.Harper's plan is not to take the centre away from the Liberals, but to polarize our political culture so that the middle ground disappears. His approach is simple: frame the issue in terms that are so black and white that everyone feels compelled to take one side or the other; then position the government on the side where public opinion is the strongest.For example, the Conservatives have become downright hawkish on international security, arguing that the terrorists have put the world in such great peril that the government has no choice but to act decisively to help defeat them.In response, the NDP has lined up on the other side, firmly opposing the campaign against ISIS and rejecting Bill C-51 (the security bill). As for the Liberals, they have had a very hard time staking out middle ground on security issues.Conservatives have also had some success at polarizing crime, so that many Canadians now see opposition to tougher sentences as being soft on criminals.Some see these successes as the canary in the coalmine. Canadian politics is becoming more ideological and more polarized and, as it does, the middle ground is disappearing. But there is another way to look at things. We can see the search for middle ground as a leadership-style, rather than just a positon on the policy spectrum. Let me explain.Terrorism and crime are hot-button issues. People have always had very strong views on them. If Conservatives have successfully polarized these debates, it is because they pitched the issues in the starkest possible terms.But not every important issue is a hot-button issue. For example, Conservatives have tried their best to polarize “the economy,” treating any departure from lower taxes and balanced budgets as a crime against “ordinary hard-working Canadians.”They've also tried this on the environment, where Harper's steadfast refusal to talk about sustainable development was clearly meant to cast environmental activism as a threat to jobs and economic growth.I don't think either has succeeded—at least, not for the long-term. While the economy was doing well, and when expert views on climate change were more unsettled, Conservatives got some mileage out of this tactic. But now that oil prices have plunged and climate change has moved into the mainstream, Conservatives are sounding increasingly defensive on both fronts. They appear to have painted themselves into a corner.There is a lesson here for everyone. We live in a highly-connected, fast-moving, global village where progress on big issues like employment or the environment almost always involves cooperation with other governments and all kinds of businesses and civil-society organizations.A prime minister that casts his policies too narrowly or too rigidly is playing a very short-sighted game. This may hamstring opponents for a time but, by the same token, it leaves no room to accommodate partners or adjust to new circumstances. And these days, that is what governing is all about. Polarization thus is a formula for isolation and, ultimately, paralysis.So, on one hand, Harper is right about the need for some new thinking around governance and leadership; but, ironically, it runs in the other direction from the leadership-style he has cultivated. The leadership we need for the future must be pragmatic, flexible and collaborative, rather than doctrinaire, rigid and controlling.So far, the leader who seems most willing to move the yardsticks in this direction is Justin Trudeau. He pitches his policies in a way that builds an unusual amount of flexibility and collaboration into them.For example, on the environment, Trudeau proposes a pan-Canadian approach, where the provinces and federal government will work together to find solutions. He doesn't say where, exactly, this will end because he doesn't know yet.For those who insist this will lead to gridlock (“You can't trust the provinces!”), first, let's note that it is the feds who are the laggards on this file, not the provinces. Second, without the provinces' full and willing cooperation, implementation of a big unilateral federal scheme will quickly become an albatross around a prime minister's neck.Rather than get caught up in the politics of old-style federalism, Trudeau smartly starts from the assumption that success will require a search for common ground with the provinces, and then pitches his policy accordingly. No posturing, no polarizing policy positions.Finally, there is a clear, if implicit, message here that Justin Trudeau has no intention of doing environmental policy the way his father did energy policy.Thomas Mulcair might want to reflect on this.Trudeau is also positioning himself differently on the economy. Unlike Harper, he doesn't see a commitment to lower taxes and balanced budgets as incompatible with a willingness to make public investments, say, on infrastructure or education.I think most Canadians will agree. Indeed, when their livelihoods are in peril, they want to know that their government is considering all the options. As for economists, most agree that such investments can be highly beneficial.New Democrats may wonder how this differs from their own policies. I think the real challenge for a prime minister that wants to consider such options is to submit them to a new level of policy discipline. The problem with public investment is not that it uses tax dollars, but that it has wasted so many of them through patronage, bad policies and pet projects.To avoid this in future, the government should subject such proposals to four basic conditions: (1) they must reflect public priorities; (2) they must be explored and implemented through an open and transparent process; (3) they must be based on evidence, expert advice and public debate; and (4) the impacts must be carefully tracked, measured and reported on.Trudeau's recent proposals on open government include a range of measures that will significantly advance policymaking on all four of these conditions. This would go a long way to ensuring that a Liberal government's decisions on investment were effective, as well as highly transparent and accountable. New Democrats have yet to propose anything nearly as comprehensive on open government.In sum, if we want better results, we need more than new policies. We need a major rethink of leadership-style. There are some good ideas surfacing and progressives, at least, should be debating them.Dr. Don Lenihan is Senior Associate, Policy and Engagement, at Canada 2020, Canada's leading, independent progressive think-tank. Don is an internationally recognized expert on democracy and Open Government. His recent projects include chairing an expert group on citizen engagement for the UN and the OECD; and chairing the Ontario Open Government Engagement Team. The views expressed here are those of the columnist alone. Don can be reached at: [email protected] or follow him on Twitter at: @DonLenihan