Lots of people are wondering why Justin Trudeau raised the abortion question now. I don't pretend to know, but if a dark cloud is left hanging over the Liberal Party, it may have a silver lining.The stage has been set for a discussion that is long overdue: How much freedom do leaders need to make controversial decisions?The traditional view is that leaders are there to lead. And that is how Trudeau explains his decision on abortion. He felt he needed to clarify the Liberals' status as a pro-choice party, so he did.Others disagree. They say Trudeau is changing the party in ways that are damaging and unnecessary, and that he should never had made such a call.Andrew Coyne, a fierce critic on this, argues there is already an established way of dealing with matters of conscience: free votes. Why not just let MPs decide?But if this option sounds attractive, it raises questions of its own:

• Do free votes on such issues risk creating deep divisions in a party?

• While abortion may raise profound moral questions, many people feel the same way about domestic abuse, child poverty or prostitution. Why give abortion a special status?

• Even if an issue like abortion is not “settled” across the society, shouldn't political parties try to move the process along by settling it within their own ranks—as the NDP has done?

As these questions suggest, if we are asking how to put some principled boundaries around the leader's right to make choices, free votes don't get us very far. The leader still has to make all kinds of controversial decisions to make them work. They may be part of a solution, but they are not the answer. We need something else, but what?To start, let's recognize that in a society as socially diverse, information-rich, and digitally connected as our own, people's interests and concerns vary greatly. And we can expect this trend to continue. As a result, people often have very different views of what is implied by a party's commitment to its basic principles and values.Take Equality of Opportunity. Applying this principle to issues such as tuition fees or equalization payments requires interpretation and leaves lots of room for disagreement. In the end, the important choices usually lie in the grey zone around the principle.To lots of people, giving leaders the freedom to make such choices is just a license to freelance. And they are increasingly resentful of party officials who insist that this kind of deference to the leader is necessary.Instead, they want a greater say in defining their party's priorities and policies or tighter control over the leader—or both. Let's revisit Trudeau's decision in this light.Trudeau recognizes that people of good faith can have irreconcilable differences; nevertheless the Liberal Party is a pro-choice party. While pro-life candidates are welcome, Trudeau says they cannot advocate for pro-life policies.We can call this a “ground rule” because it clarifies the party's basic values—in this case, its pro-choice status. As a result, it sets a new standard that applies to MPs and members. But note that it also applies to the leader, as he/she would no longer have the authority to approve a candidate that did not accept the ground rule.Now let's ask whether Trudeau had the right to create this ground rule. While the answer is controversial, let's say that he did. Would he have the right to approve a list of such ground rules?I don't think anyone would say that he does. It is hard to imagine that any leader could do that without provoking a serious reaction from the rank and file.Nevertheless, as we've seen, pressure is building on leaders to define rules that clarify their authority. In the future, we can expect to see more and more ground rules.There is thus a kind of Catch-22 here: The more people challenge the leader's right to make controversial choices in the grey zone, the more controversial choices leaders need to make in order to clarify the grey zone.This is the dilemma Trudeau is caught in and, as far as I can tell, there is only one way out: greater transparency and engagement. Party members must have a say in setting these rules. As it turns out, this is a position Trudeau already says he fully supports.Recall that when critics were calling on him to release a policy platform, he replied that he wasn't going to do the usual thing of getting a few senior officials around a table to hammer one out.Instead, he said he wanted to travel the country and talk to ordinary Canadians and Liberals about the values and principles of the Liberal Party and what they want to see in the platform.Trudeau's goal was to give ordinary people a voice in defining the party's values and making policy choices. I don't know where this project now stands, but the controversy over his abortion decision highlights the growing need for exactly this kind of engagement. It allows the leader and the party to work together to shape and legitimize ongoing decision-making in the grey zone.For example, Trudeau says he believes in the need for investment in education and he has made education a priority. Ideally, he would be already out there building consensus around ground rules to set some limits on this kind of public investment. This would clarify the scope for decisions on the issue, while legitimizing the choices when they come.Exactly how the process should work is open to discussion, but the need is clear. The problem of legitimacy is real and growing and it will raise its head again—and not just for Liberals.Dr. Don Lenihan is Chair of the Ontario Open Government Engagement Team and Senior Associate at Canada's Public Policy Forum in Ottawa. He is an internationally recognized expert on democracy and public engagement, accountability and service delivery. Don's latest book, Rescuing Policy: The Case for Public Engagement is an introduction to the field of public engagement, a blueprint for change, and a sustained argument for the need to rethink the public policy process. The views expressed here are those of the columnist alone. Don can be reached at: [email protected] or follow him on Twitter at: @DonLenihan