Canada is in the grip of election fever, and the only prescription is casting a ballot on Oct. 19, 2015.

It's a tight race between current Prime Minister Stephen Harper (Conservative), Justin Trudeau (Liberal) and Thomas Mulcair (New Democratic Party).

The choice voters make will shape relations between Canada and the U.S. for years to come.

Here are four reasons why this election matters to Americans:

The Marijuana Market

where.ca

The Issue: The legal status of cannabis could change relations between Yanks and Canucks for three reasons:

A. Border battles: since cannabis remains illegal in most states, officials will have to be extra-vigilant when monitoring international traffic along the world's longest unprotected border.

B. Vape-cations: Canada could become the next Netherlands: a tourist destination for people looking to enjoy legal weed. Sure, Americans could visit the legal states, but for people in Maine, Michigan, or Montana, it might be more convenient to head north.

C. A Rival Market: one of the main engines driving legalization initiatives in the U.S. is the prospect of cannabis becoming a cash crop. But will that market shrink due to competition from Canada?

The Stances

Stephen Harper opposes legalization and decriminalization.

Justin Trudeau is pro-legalization.

Thomas Mulcair pledges to decriminalize cannabis on his first day in office.

A Hawk in Dove's Clothing?

forces.gc.ca

The Issue: The nation that invented peacekeeping has been feisty lately. Canada, which once championed "soft power" and abstained from the Iraq War (2003-11) despite pressure from American and Canadian politicians, is now a country that tells Russia to "get out of Ukraine" and bombs ISIS.

Will the Canada of 2016 continue this belligerent streak, or will it lapse back into its pacific role? Here's the outlook for the year ahead (focusing on ISIS).

The Stances

Stephen Harper began Canada's combat mission against ISIS, and promises to continue it.

Justin Trudeau proposes to end Canada's combat role with ISIS and to focus on training local forces to fight the insurgents.

Thomas Mulcair pledges to end the fight with ISIS immediately.

A Crude Awakening?

macleans.ca

The Issue: Keystone XL is a proposed pipeline that would connect the Alberta oil sands (aka "tar sands") to the Gulf of Mexico, transporting approximately 830 000 barrels per day for refinement. The pipeline could create jobs and make oil processing more efficient. Opponents of the project are particularly wary of the impact it could have on the environment.

The Stances

Stephen Harper lobbied aggressively for the pipeline and voiced frustration when President Obama rejected it. He hopes to see Keystone move forward following America's regime change in 2016.

Justin Trudeau supports Keystone and pledges to find a way to keep pipelines environmentally friendly.

Thomas Mulcair denounces Keystone as an unsustainable project that will export Canadian jobs along with oil.

Arctic Sovereignty

haikudeck.com

The Issue: The discovery that the Arctic contains massive fossil fuels sparked a flurry of territory claims: Canada, America, Russia, Denmark and Norway have all made claims to the region. This map published by The New York Times highlights the contested areas of the north, and the region's richest resources.

The Stances

Stephen Harper has pledged to arm and defend the arctic as part of Canada's economy and national identity, calling the territory "central to our identity." He added, "Through our Northern Strategy we will continue to exercise our sovereignty over the Arctic. We will continue to invest in infrastructure….in social and economic development, as well as in environmental protection."

In 2014, Justin Trudeau said he would "defer to scientists" regarding who owns the arctic. But on Sept. 28, 2015, he rattled his sabre by scoffing at Harper's record of defending Arctic sovereignty: "The only thing they keep saying about you up there Mr. Harper is you're big sled, no dogs."

Thomas Mulcair has similarly championed Arctic sovereignty while suggesting the Harper government's negligence is allowing the territory to slip out of Canada's control: "Under Stephen Harper, Canada has fallen behind in our work assuring Canada's sovereignty of our part of the Arctic….They haven't done any of the things that they've promised they would do. In fact, we're rolling back."

Over to you, America: Which one of these three would you like to see lead America's oldest ally? And which candidate do you think would pair best with the current contenders for the Republican and Democratic Nominations?