The pipeline extension will travel through Montana, South Dakota, Nebraska, Kansas, Oklahoma and Texas. The reception in each of these states is mixed, with support and opposition to the project crossing party lines.
Opposing the project is an unlikely mix of interests: farmers, ranchers, and environmental groups, all of whom worry about the effect any leak would have on the land.
Unlike other Republican governors, Nebraska Gov. Dave Heineman had asked Obama to block the pipeline on the grounds it risks the health of the Ogallala aquifer, a major source of fresh drinking water for people in the region as well as for livestock and agriculture.
Governor Heineman says he will support the project if the pipeline is rerouted to avoid the aquifer, 65 percent of which is in his home state.
Other opponents say the corrosive tar-sand-derived crude is difficult to clean when spilled. And environmentalists point to an even broader concern, saying that extracting petroleum from tar sands creates more greenhouse emissions than conventional oil production, releasing more carbon into the atmosphere and accelerating global warming.
Regulation is also an issue. The Gulf of Mexico oil spill revealed the cozy relationship between federal regulators and the oil and gas industry; opponents worry that the same will happen here and that the Transportation Department’s Pipeline and Hazardous Materials Safety Administration is too small to handle a project as large as Keystone.
The coalition pushing for the pipeline is just as unlikely: unions and business leaders, both of whom say the pipeline will boost local economies and create jobs.