When Stephen Harper's government was defeated in 2015, we tried to figure out what drove its thinking on foreign policy. We did so by comparing the government's approach to a variety of international issues before and after the Conservatives won a majority of seats in the House of Commons in 2011.

What we determined in our book The Harper Era in Canadian Foreign Policy is easy to capture in a soundbite, but takes more time to explain: Parliament matters when it comes to Canadian foreign policy, even though it doesn't.

Here's what we mean.

Constitutionally, foreign policy is a responsibility of the Canadian executive.

Even though opposition parties in a minority Parliament can push foreign policy bills through the House, like the 2007 Kyoto Protocol Implementation Act or the 2008 Official Development Assistance Accountability Act, Harper's Conservatives proved that a minority government can ignore such legislation.

On the other hand, minority Parliaments often present incentives for governments to consult with the House of Commons more than they might when they hold a majority.

The Tories and Afghanistan

Consider the Conservatives' approach to Afghanistan. One of the easiest ways to diffuse potential opposition criticism of the Canadian mission in Afghanistan was to hold a vote on extending it.

Once the Liberals voted in favour, it became significantly more difficult for them to criticize the mission as a whole. Philippe Lagasse, an international affairs expert at Carleton University, calls this tactic laundering.

During the Harper era, the government's standing in the House of Commons also affected the pace of international negotiations. In a minority Parliament, ministerial travel is severely restricted. The government can't risk having too many of its members unavailable for a surprise vote in the House of Commons.

There's also reason to believe that the Conservatives' standing in the House of Commons mattered when it came to the amalgamation of the Department of Foreign Affairs and International Trade with the Canadian International Development Agency.

Derek Burney, who ran the Harper government's initial transition team, has noted that the prime minister contemplated the merger in 2006, but concluded that it was a bridge too far for a new government, particularly, we might suggest, because of its minority situation.

Once the Conservatives gained their majority, they pushed the merger through easily.

More willing to court controversy

The Harper government's willingness to take controversial public positions on human rights issues also intensified as its numbers in Parliament increased. In both 2006 and 2009, for example, the Conservatives did not rule out signing the Optional Protocol to the UN Convention against Torture. In 2013, however, they stated bluntly that the government had no intention of signing any outstanding human rights treaties.

And while some might attribute the change to a government that became more experienced, or to a more outspoken foreign minister in John Baird, the extent of the government's willingness to risk isolating itself within the international community appears to have been influenced, at least in part, by the sense of political security that came with its 2011 majority.

On the other hand, a number of foreign policy issues from the Harper era were immune from the concerns of parliamentary politics.

Take national defence, for example. Historically, Ottawa's commitments to a robust defence capability have been shaped primarily by the state of the Canadian economy.

The Harper era was no different. Funding for national defence surged during the early years of budgetary surpluses, and slumped during the recession and subsequent campaign for balanced budgets.

Environmental progress

Environmental reform had a different determinant: the United States. The Harper government seemed quite clear that it would make changes to its environmental policies as slowly as Washington would allow, and it maintained that position through the minority and majority years.

Discussions of foreign policy in parliamentary committees were different during the minority years, when the Conservatives could not control the committees' agendas. But whether those debates actually caused the government to change its policy is less clear.

So what should we expect as Justin Trudeau's government acclimatizes itself to its minority standing in the House of Commons, in addition to an unpredictable Senate?

If the Harper era is any guide, the makeup of Parliament will matter to Canadian conduct in world affairs, but there's nothing official that forces a minority government to behave differently than a majority government on the international stage.

Nonetheless, minority Parliaments create a political environment that discourages cabinet from acting boldly.

We should therefore be prepared for an even more risk-averse and conservative foreign policy than the one we already have.

There is, of course, a different way that this could play out. Our political leadership could seize the opportunity to negotiate a non-partisan statement of Canada's national interests.

Those interests could serve as a basis for any Canadian government, and thereby provide Global Affairs Canada with the stability and understanding that it needs to maximize Canada's impact and effectiveness on the world stage.

This scenario is highly unlikely, but it doesn't hurt to hope!

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Authors: Adam Chapnick - Professor of Defence Studies, Royal Military College of Canada | Christopher Kukucha - Professor, Department of Political Science, University of Lethbridge