Political greatness takes talent, but it also takes opportunity and courage. Canadians have just handed Justin Trudeau an extraordinary opportunity, but does he have the courage to do something exceptional with it?Before answering the question, let me start with a brief detour stateside, where there's a powerful lesson for Trudeau.When Barack Obama took office in 2009, the world's financial system was on the brink of collapse. Whether he wished it or not, history assigned him the task of averting disaster and fixing the system. Success would have given him a legacy on the scale of FDR's New Deal or JFK's moonshot.But Obama's closest advisors were divided on how to proceed. One side saw the crisis as an opportunity. They thought the government's massive bailout of the financial sector gave the president the leverage he needed to carry out a full-scale restructuring of the big banks.The other side worried about timing. They feared that massive intervention in the banking system during such a crisis might stampede investors, causing a run on the banks. They insisted on a cautious, incremental approach.Obama summoned his aids to the Oval Office and instructed them to argue the case in front of him. And they did—for six straight hours. The president ended the meeting without signalling his intent, one way or the other.A few days later, Obama assembled the CEOs of the floundering banks, then announced that he was there to help them. The bailout would continue, and there would be no immediate restructuring. Obama had chosen the path of least resistance.Recognizing they had just dodged a bullet, publicly, the CEOs showered the president with praise and promised to work arm-in-arm with the White House to rebuild the system.Six months and six hundred billion tax dollars later, the financial storm had abated and calm was returning to Wall Street. The president felt he now had the conditions for reform.So he called on the bankers, whose cooperation he needed. Much to his dismay, they ignored him. They had never wanted reform and with the crisis over, they knew his leverage was gone. He had missed the moment.The lesson for Trudeau is clear. There are moments when circumstances align and a skillful leader can use his or her office to leverage major change. Such moments cannot be planned or manufactured. They are extraordinary opportunities that history alone confers.Great leaders not only recognize such moments, they seize them—even though it may plunge them into uncharted waters. Greatness requires real risk. And that is where courage comes in.I think this explains a lot about Obama. For him, the decision to restructure the banks was such a moment—and he blinked. His presidency never really recovered. As a result, a potentially great leader will go down in history as, at best, a good one.Like Obama, Trudeau appears to be standing at history's crossroads. He used the campaign to say what he believes is wrong with Canadian politics; and in the process he won Canadians' trust. They felt the huge cramp in their political system and they told him to fix it.As he notes, however, the problem is not just Stephen Harper. The Harper government was the logical conclusion of a long-standing centralization of power in the PMO that began with Pierre Trudeau.The trend has been aided and abetted by an insidious lack of transparency across the political system. If Canadians want to prevent a return to this style of politics, they must do more than vote Harper out. They must stamp out the culture of secrecy and control on which this kind of politics thrives.Real Change thus is more than rejigging the tax system to benefit the middle class; or taking a more moderate stance on the world stage; or even making a concerted effort to bring sustainable development to the fore.Real Change calls for a comprehensive reform of our system of governance, a redesign of the very process by which such decisions are made.But let's not kid ourselves. This is going to be hard. Politicians and politicos of all stripes will resist, some fiercely. They have cut their teeth on the politics of secrecy, control and spin and many can scarcely imagine anything different.When push comes to shove, the idea of overhauling the system will scare the daylights out of them—just as breaking up the banks was too big, too ambitious, too risky to be contemplated by many on the Obama team.And, in the end, by Obama himself.Over the last two months, I have been asking people what they think of Trudeau's plans for open government and reform. While most believe the ideas are sound, they doubt there is the political will.Once in office, they say, the Team will benefit from the same kind of secrecy and control that outraged them in opposition. In addition, the risks associated with major change will seem too great. As a result, plans for change will be watered down, until there is just enough left to let the government claim it has delivered on its promises.Where does that leave us?The hope Canadians felt when Barack Obama was elected reminded many of us of how we felt about John and Bobby Kennedy, two generations ago. We looked on the new American president as though he were ours.Seven years later, the disappointment is crushing. The soaring speeches and provocative invitations to imagine something great have crashed and burned. We are left asking why.The answer is at once wrenching and banal. At a critical moment, our champion lost his nerve. He blinked and we missed our rendezvous with history and greatness, as did he.The lesson for Trudeau is quite simple, really. Trust yourself, Mr. Prime Minister, as you've asked us to trust you. Don't be dissuaded by the chorus of naysayers, chanting the hundreds of reasons why it can't be done. Greatness requires risk—and courage.Just do 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