Conservative Leader Rona Ambrose wants a referendum on electoral reform. I suspect she'll get one. The government really doesn't have much choice. The more interesting question is about what will be on the ballot. And here we could be in for a surprise.Over the last decade, BC, Ontario and PEI have all taken a run at changing their electoral systems; and all felt obliged to wrap up the process with a referendum. In all three cases, a super-majority of 60% of the overall vote in 60% of the ridings was required to confirm the change. BC and Ontario also held scrupulously non-partisan citizens' assemblies.As a result, a referendum is now widely seen as the norm for such a change and departing from it would be politically risky. Electoral reform is not just another policy issue where the government can claim a mandate to choose the solution. As Ambrose says, this is about fundamental change to the system.I find it hard to believe the Trudeau government is oblivious to this, which means, I suspect, that a referendum is all but certain. But why be coy about it? Maybe the government is trying to keep its options open on how it will use the referendum ballot. Let me explain.On process, the government has already declared its intentions. The Minister of Democratic Institutions, Maryam Monsef, will propose an all-party committee to consult with Canadians. The government says it wants to have a fair and open discussion of the options.However, as CBC's Eric Grenier has noted, the parties have already lined up behind the approaches that favour their electoral prospects. Liberals favour ranked voting, the NDP wants some form of mixed proportional system, as do the Greens, and the Conservatives favour the status quo. So the parties are quite literally all over the map on this.Moreover, because these options have been debated for years, and because there's so much at stake, none of the parties is likely to change its position as a result of the consultations. It will be very difficult to put partisan interests aside.Not that the process lacks merit. There are sound arguments for all three options and lots of citizens have yet to make up their minds. Encouraging them to get engaged, work through the issues and make their own choices is good for democracy.Through this debate, however, citizens too will almost certainly become divided on the options, which, in turn, will give committee members some cover to line up behind their preferred choices. As a result, there is an excellent chance that when it comes to writing the final report, committee members will fail to rally around a single proposal.Now imagine the following scenario: the NDP issues a minority report calling for proportional representation; the Conservatives do the same, arguing for the status quo; and a majority Liberal report proposes ranked voting. Normally, referendum questions are framed as a simple Yes or No. What does the government do?If it really wanted to stick to a simple Yes-or-No question, it could choose to act on the (Liberal) majority report and pose that option on the ballot. But if it did the NDP would rightly scream blue murder during the campaign.Another possibility would be to put both Ranked Voting and Proportional Representation on the ballot, along with a third option of “None of the Above,” which is effectively the status quo or the Conservative choice. I see no reason Canadians couldn't be asked to choose between three options.However, in this scenario it is quite possible—perhaps likely—that no option would win majority support, let alone a super-majority. Changing the electoral system with less than a majority of the votes is almost certainly not on. Presumably, then, such a result would kill the two new options, which, in effect, would be a victory for Conservatives.One way to solve this dilemma would be to ask voters to rank their preferences on all three options—that is, to use preferential voting. This wouldn't be a stretch for the Liberals, as that's the option they favour for a new electoral system. But if this solves one issue, it raises others.For one thing, a super-majority would likely be unattainable. Although, given the plurality of choices, the government—and Canadians—might be satisfied with a simple majority.Another downside, at least from a political perspective, is that it would make the outcome very hard to predict. How voters will rank their second choice could be critical, but extremely uncertain. It's also likely to lead to a messy and highly divisive referendum campaign. The government may just have to live with consequences like these.In sum, given the reform process the government has chosen, the odds are good to excellent that the parliamentary committee will fail to agree on a single option. Nevertheless, the weight of past precedent will almost certainly force the government to hold a referendum.If it does, I don't see how it can put its preferred option to Canadians, while sidelining an NDP minority view, and then claim the process has been open and fair. That would look like the worst kind of majoritarianism on a very fundamental question.So as far as I can tell, a split committee leaves the government with one option: ranked balloting. Then again, maybe the Liberals have a better answer up their sleeve. If so, I'll be keen to see it.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. He is currently the Government of Ontario's principal advisor on its Open Dialogue Initiative. The views expressed here are those of the columnist alone. Don can be reached at:[email protected] or follow him on Twitter at: @DonLenihan