There's a scene in The Godfather that ties up the many strands of the plot into a sudden series of conclusions in a single day of mob hits when Michael Corleone "settled all family business." In Ottawa, the next month is going to be a little like that, in a bloodless way, as many of the plot lines of Justin Trudeau's first year come to a denouement in a rat-a-tat series of announcements.

The politics will be unavoidably messy. And, like the climax of The Godfather, we're about to learn if the main character has a ruthless streak.

The next month is heavy with issues key to Mr. Trudeau's Liberal agenda, from peacekeeping to electoral reform, to a tangled knot of decisions on pipelines and climate policy.

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The PM might be able to dodge hard decisions on some: When a task force on legalizing marijuana reports Nov. 30, his government will try to delay responding with its plans. It will be harder to stall on electoral reform when a parliamentary committee reports Dec. 1, especially if, as expected, opposition parties insist that any reform must be approved by referendum. That will press Mr. Trudeau to say if he will keep his promise to reform voting for the next election – the Liberals will try to delay but the time needed to plan for election changes is running short. Already, Democratic Institutions Minister Maryam Monsef is indicating the Liberals will back off if there isn't broad support

And the Liberals have promised to announce plans by the end of the year for deploying up to 600 peacekeepers to Africa. It is, for Mr. Trudeau, a telling choice. His Defence Minister, Harjit Sajjan, has warned that modern peacekeeping means risk and danger, and UN officials have urged Canada to take on a key role in the most dangerous UN mission, in Mali. Now, Mr. Trudeau must decide if Canadians will really accept the prospect of casualties in a complex mission that will continue through his mandate – or choose a safer course.

But the biggest nexus of decisions will come in the energy and environmental issues that Mr. Trudeau has insisted he can balance.

This week, the government will announce whether it will approve the expansion of Enbridge's Line 3 pipeline from Alberta to Gretna, Man., where it links with a U.S. pipe, allowing the export of an additional 370,000 barrels of oil a day.

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At the same time, it must announce whether it will finally quash the Northern Gateway pipeline through the Great Bear Rainforest to Kitimat, B.C. That was approved by Stephen Harper's government, with conditions, but the approval was nixed by a court because First Nations were not adequately consulted. Now, Mr. Trudeau – who has insisted Great Bear is no place for a pipeline – must say if he will kill it once and for all. That, in turn, would make it easier to deliver on a ban on oil tankers off B.C.'s northern coast, promised by the end of the year. That ban is likely to be weaker than some Liberal voters want, but if there's no Northern Gateway pipeline, fears of an explosion of tanker traffic off the coast will be allayed anyway.

But the defining decision is on Kinder Morgan's Trans Mountain pipeline to Burnaby, B.C., due by Dec. 19. Mr. Trudeau promised he could address both climate change and get oil to export markets. He's under pressure, in a soft economy, to approve a pipeline. His government has been preparing the ground to greenlight Trans Mountain.

But it requires some political ruthlessness – it will upset allies such as Vancouver Mayor Gregor Robertson, and clobber two Lower Mainland Liberals MPs, Terry Beech and Ron McKinnon, who oppose it. Approval will spark protests in B.C. and turn some Liberal supporters into opponents.

Mr. Trudeau has appeared willing to take that risk because it could lead to a political triumph. If he can balance a pipeline with a climate deal with premiers at a meeting Dec. 8 – and it appears a deal with all provincial premiers except Saskatchewan's Brad Wall is likely – then he can claim the broad political middle by asserting he delivered both a pipeline to tidewater and a deal on emissions.

It also means massive risks: battles with his own base in B.C., the possibility that environmental voters are angered by pipeline approvals while pro-development voters agree with Mr. Wall. The political middle might shrink.

For a year, many of these issues have stewed, Now, Mr. Trudeau is slated to make a series of decisions that will show his appetite for risk.