Today, more than a million barrels of crude oil will be transported by rail to the United States from Canada. This is business as usual, as the U.S. relies on Canada for 15 percent of its oil supply. But amid the heated debate surrounding the proposed 1,700-mile Keystone pipeline, this may come as a surprise. Despite our current supply relationship with Canada, many environmental advocates have picked this project as their line in the sand (tar-sand, really), and their stance has received mixed reactions from the sidelines. A recent report published by the State Department on Mar. 8 has polarized the issue further, suggesting that the project itself will have minimal environmental impacts and should move forward. All eyes are on President Barack Obama now, as the stroke of his pen will settle this issue. Despite the State Department’s advice, the environmental community has picked the right battle.

The Canadian corporation TransCanada first submitted its application for a Presidential permit, the authorization needed to approve the Keystone pipeline, back in 2008. As envisioned, the pipeline’s sections would travel from Alberta, Canada, to the heart of the Midwest and eventually make its way to refineries in Texas. In total, we could count an additional 830,000 barrels of oil per day from this new artery. But there is one thing to keep in mind: Canada isn’t exactly gushing with oil. Unlike most oil producing countries, Canada’s supplies are tied up in tar sands: a viscous sludge that has no business being anywhere near your gas tank. The preferred method for recovering these tar sands from deep underground is known as Steam-Assisted Gravity Drainage: Two wells are dug, one to pump steam underground (heating the tar, making it more fluid) and another to pump the sands to the surface. This process — as well as the refining and transportation of such an uncooperative substance over a great distance — is energy and resource-intensive. According to a report released by the Congressional Research Service, by the time a drop of tar sand oil is ready for your gas tank, it will have been responsible for the release of almost twice the greenhouse gas emissions of normal processed crude oil, and up to twenty percent more when it is finally burned.

This is not to say that supporters of the Keystone project have just been blowing smoke. It is very possible that the pipeline can deliver crude oil with minimal on-site environmental impacts. And even if the U.S. pulls out of the deal, Canada’s tar sands will be bought up one way or another. But while supply always meets demand, the U.S. consumes 20 million barrels of oil a day, a fifth of the global thirst. That kind of buying power is enough to set an example for the world. If we tap further into Canada’s tar sands, it is a sign that we are willing to scrape the bottom of the barrel, spending even more energy to get it. The environmental movement is justified in its efforts to pressure the government, even though the U.S. may just end up shopping elsewhere if Obama moves to block the project. At the end of the day, it is in the hands of Americans to justify a rejection of the Keystone pipeline by reducing their demand by just as much.