Senate hearings on C-69 are about to begin and the critics are lining up. It will be a critical test of the government's approach to climate change AND of the new senate's role as a house of sober second thought. There's a lot hanging in the balance and senators need to get this right. So, what should they do?Let's start with a quick review of the bill.C-69 establishes a new process for assessing the environmental impact of major resource projects, such as a new pipeline or a mine. The goal is to ensure that development is sustainable. Let's break this down a bit.First, “sustainability” means recognizing that some of our fundamental goals (e.g. protecting the environment, strengthening key social values, promoting economic growth) can conflict in ways that undermine one another. For example, a mining operation may create jobs, but destroy wildlife habitat.Ensuring development is sustainable also means the government will take steps to balance these interests when they conflict. Thus, it might protect wildlife habitat by imposing restrictions on how a mine can operate or, in some cases, by preventing mining altogether.But “balancing” competing interests is a tricky business. People disagree on how and where government should step in and change things. For example, they have different views on how much carbon an industry should be allowed to emit. Some worry more about protecting jobs, others worry about the impact on the climate.C-69 is supposed to resolve such disagreements by defining a process for balancing economic interests against environmental or social ones. The process it proposes is multi-faceted and complex, and critics have taken issue with just about every part of it. Much of this can be summed up in two basic points:The criteria/steps for assessing a project's impact are often confusing and unclear.Take consultation: while the bill establishes new opportunities to engage Indigenous Peoples, it fails to explain how these will fit into overall decision-making. Do Indigenous Peoples have a veto over development or is the government simply trying to find common ground with them?The bill grants the minister far too much discretion to make decisions on key parts of the process.Thus, the minister has the right to decide whether an assessment is required, to extend deadlines, and to make decisions without fixed criteria.According to the critics, these two issues recur throughout the bill, thus undermining its promise to provide clarity and predictability. Instead, they believe it will result in greater uncertainty and ad hoc decision-making.The government of course disagrees. It says the process is tough enough to carry out these assessments; and it argues that discretion provides the flexibility the minister needs to respond to complex circumstances.So, who is right? Are the public well served by discretion and flexibility or do they need a process with more clarity and predictability?In fact, clarity and predictability are not hard to get. Senators could easily tighten up the process, first, by limiting ministerial discretion; and, second, by sharpening the criteria for balancing economic development and the environment.But that's where things get complicated. These steps will have a further consequence that critics rarely mention: they will almost certainly tilt the process – perhaps sharply – toward either a more ambitious definition of sustainability or a weaker one.Senators should recognize that in order to define a “better balance,” first they must decide where they think a better balance lies. And that depends on your politics.Those on the right define it in ways that would pull the bill back toward more conventional economic development. Those on the left want to add criteria that would push it toward a more ambitious commitment to sustainability. Clarity and predictability thus come at a price.So far, the government has been cautious about both. It has defined its commitment to sustainability loosely as “balancing economy and environment,” and then approved projects it says are “in the public interest.” In the absence of a clearer process, this left the government with lots of leeway, that is, “discretion.”Thus, it was able to declare that the Northern Gateway pipeline was not in the public interest (it seems to be leaning the same way on Energy East), while declaring that Trans Mountain was.C-69 is a step toward greater clarity on sustainability, but it retains much of the open-endedness (critics would say “vagueness”) of the government's approach. Hence there is pressure from both industry and environmentalists for more clarity and precision.Should senators decide to provide it, first, they will have to choose which way to lean – toward or away from sustainability. Who should they listen to? Critics on the right or the left? Which side counts as sober second thought?Canadians are at a crossroads and how this question gets answered matters greatly – for industry, the environment, and the country. The government will likely have to make some hard choices about it, and soon.But here's the thing: I don't think it is up to senators to make them for the government. The consequences are too deep and far-reaching.Decisions like these should be left to duly elected officials – and, ideally, sanctioned by an election. The senate should be low-keyed and cautious.Dr. Don Lenihan is an internationally recognized expert on public engagement and Open Government. He is currently advising The Ottawa Hospital on an engagement plan to develop its new Civic Campus – a $2 billion, 10-year project. He also co-chairs the Open Government Partnership's Practice Group on Open Dialogue and Deliberation. Don can be reached at: [email protected] or follow him on Twitter at: @DonLenihan