By Nick Engelfried
Big Sky Weekly Columnist

In Montana and throughout the nation, environmental activists and their allies are celebrating a hard-earned victory.

After months of work, more than a thousand peaceful arrests, and a rally that brought thousands of people to the nation’s capital, the Keystone XL tar sands oil pipeline has been dealt a major setback, as politicians decided to put a decision on hold for further review.

If built, the 1,700 mile long Keystone XL pipeline would stretch from the Alberta to Texas. Along the way it would cross through eastern Montana, slicing across the property of dozens of private landowners. Though Gov. Brian Schweitzer supports the pipeline, affected landowners have expressed worries about safety.

In September, 34 Montanans whose property sits in the pipeline path signed a letter to the Montana Department of Environmental Quality, asking that an oil spill response plan be made available. The landowners pointed to the risk a pipeline rupture would pose to nearby communities, and emphasized the need for emergency response personnel to be fully prepared for an oil spill.

Public officials in Nebraska, including Republican Gov. Dave Heineman, have urged the pipeline be re-routed to avoid the sensitive Ogallala aquifer. Environmental activists across the country also made stopping Keystone XL a priority, because the pipeline would solidify U.S. dependence on a particularly dirty form of oil.

During two weeks in late August and early September, more than 1,000 people were arrested in front of the White House as part of a protest against the pipeline. Montana actress Margot Kidder was among several celebrities arrested.

Now the work of Kidder and thousands of others is paying off.

On Nov. 10, the U.S. State Department announced a delay in the Keystone XL permitting process. The project backer, Calgary-based TransCanada, is now required to draw up a new route for the pipeline, which will undergo scrutiny from the State Department. Because the pipeline crosses a national border, they must decide if it’s in the country’s national interest before Keystone XL can move forward.

The State Department’s announcement came days after thousands of people gathered in Washington, DC to circle the White House and demand that the Obama administration reject the pipeline. The project, which once seemed on track for approval by the end of the year, won’t make it through the review process until late 2012.

The long-term implications for Keystone XL could be even more serious. The delay before construction, combined with uncertainty of the State Department approving the pipeline, could nix the project.

This year’s ExxonMobil oil spill in the Yellowstone River shined a spotlight on risks inherent in transporting oil through pipelines. The spill, caused by a pipeline rupture, polluted more than 150 miles of riverbank with residue that hasn’t been completely cleaned up. A rupture in Keystone XL could be even more disastrous; the proposed pipeline would be 36 inches wide, three times the diameter of the pipeline involved in the Yellowstone spill.

Though Keystone XL is not dead yet, for the moment Montana landowners and others affected by the project have been granted a temporary respite. Meanwhile Keystone has been dealt a major blow—one that could eventually turn out to be the pipeline’s undoing.