The contentious Keystone XL oil pipeline was not laid to rest when the U.S. Senate voted Tuesday to kill it.

It will get new life next year, when the Senate’s newly elected Republican majority says it will approve construction of the privately financed project. President Barack Obama threatened to veto Tuesday’s bill if it passed, but he’s likely to sign on next year after using his approval as a bargaining chip with the GOP.

But why has Keystone inspired such impassioned political theater? The United States already has 151,912 miles of pipelines conveying crude oil. Why the fuss over an additional 875 miles to bring oil from Alberta, Canada, to refineries on the Gulf of Mexico?

Because the fight isn’t really about this one pipeline.

Keystone has become a raucous proxy for the broader battle of climate change versus economic growth — with an unhealthy dollop of election-year politics thrown in for good measure.

Extracting heavy crude from tar sands is a dirty business. The process generates greenhouse gases that drive climate change. Environmentalists say without the pipeline, that oil will stay in the ground.

The facts are less black and white. Alberta crude is already being extracted and shipped by rail. So is oil from North Dakota that would be transported via the pipeline, and train derailments have resulted in a number of spills. The State Department’s environmental review concluded that sending the oil by pipeline would do less environmental harm than moving it by rail, truck or barge. And blocking construction of the pipeline would not prevent extraction of the heavy crude. TransCanada’s Plan B is to build a pipeline through Canada to transport the oil to the Pacific Ocean en route to China.

For many proponents, what’s important is increasing the world’s supply of oil and generating 3,900 or more jobs to build the pipeline. Foes are right that almost all of the jobs are temporary, but the opponents’ extraordinary efforts are best directed at putting in place carbon-reduction policies that would spur the nascent alternative-energy industry and its vast potential to create permanent jobs.

Still, on the merits, the pipeline should be approved. But that’s not why, after years of blocking a vote, Senate Democrats suddenly allowed one Tuesday. They did it to help incumbent Sen. Mary Landrieu in her Dec. 6 runoff election with Republican Rep. Bill Cassidy in Louisiana, where refineries are located and oil is king.

The pipeline decision is Obama’s to make, by law, because the pipeline would cross a U.S. border. He has promised a decision early next year, once a weak legal challenge to the route in Nebraska is resolved.

We wish the world weren’t reliant on fossil fuels. But for now it is. So once the curtain comes down on the political theatrics, the pipeline should be built. And environmentalists can move on to the climate change fights that really matter.