It seems difficult for many to take seriously regression analyses that find little relationship between public opinion writ large and the direction or degree of policy change. One would think that politicians who ignore public opinion would find themselves ex-politicians in relatively short order.

No, politicians do not ignore public opinion. They appease it. But they rarely appease it by changing policy in any substantive way. They appease it by staging theatrical political dramas full of sound and fury signifying little. The play sells because the public cannot differentiate between political fights where the stakes are high from those where the stakes are trivial or nonexistent.

The present fight over the Keystone XL Pipeline is a tremendous case in point. Here’s what you need to know. First, the oil in the Canadian tar sands will get to the market one way or another. The only issue is whether it will be delivered by this pipeline, another pipeline, or by rail. Second, the jobs at stake are trivial; a few dozen permanent jobs and a few thousand temporary construction jobs. That’s it.

And yet the Senate has thrown itself into a political cage fight over the pipeline this week (a final vote is mercifully scheduled for today). Both sides are served by the sound and fury. Environmentalists think their champions are bravely holding the line against greenhouse gas emissions (which will follow regardless of whether the pipeline is built) and conservatives think their champions are bravely sallying forth to deliver a major economic stimulus in the teeth of rabid environmental opposition. Both sides appear to address public concerns (global warming and high unemployment) but neither is doing anything tangible about either.

It is too easy to blame the general public for confusing fiction for fact. Even those strutting about the stage appear to believe that their Keystone talking points are grounded in reality. Elites with enough motivation and brain-power to learn the truth are likewise taken in by the show. It is fair to say that most people in the political world take the Keystone Pipeline fight very seriously.

Regardless, the fight serves a purpose. It demonstrates to the public that their concerns are being heard and reflected by their chosen champions in Washington. By sating the public with a meaningless political theater (the louder and more strident, the better), governing elites can go about their business with minimal interference from voters. After all, haven’t they proved their bona fides by fighting the good fight over Keystone (and other symbolically potent debates)?

This is the grown-up view of government. And it explains one very important reason why public opinion rarely constraints politicians. The public is easy misled.