The Keystone XL pipeline will usher in an economic boom, creating thousands of jobs and playing a critical role in providing affordable energy for America.

The Keystone pipeline will help trigger a global environmental catastrophe, spurring climate change and destroying the earthly inheritance for future generations.

That, without much exaggeration, sums up the debate over construction of the last, northern leg of the Keystone pipeline, designed to bring oil from the tar sands of Canada to refineries on the Texas Gulf Coast. It’s a political debate that breaks — with notable exceptions — along partisan lines, and it is played out both nationally and in the current race for the U.S. Senate in Louisiana, where it takes on its own unique and convoluted twists and turns.

And it will surprise no one over the age of 7 that ... well, pick your cliche: Both sides are wrong; the truth lies somewhere in between; or, there’s more heat than light in the debate.

Keystone stepped back into the U.S. Senate spotlight Wednesday, when the Energy and Natural Resources Committee approved a bill that would bypass the White House and give the go-ahead for the project. Because the pipeline would cross an international border, it needs Obama administration approval — but President Barack Obama, a Democrat, has delayed a decision for years.

The bill is sponsored by the committee Chairwoman Mary Landrieu, D-La., and U.S. Sen. John Hoeven, R-N.D. Landrieu is one of 11 Senate Democrats who have come out for Keystone, from the coalition of 53 Democrats and two independents that rules the Senate.

The committee discussion produced apocalyptic warnings from Bernie Sanders, I-Vt., about the looming ecological disaster, and sharp words from Republicans about the role of Obama and Senate Democrats in blocking this wholesome and wonderful project. Landrieu spoke for the bill, and with her vote, that of Democrat Joe Manchin, of West Virginia, and those of the minority Republicans, it passed 12-10.

Which produced outrage from U.S. Rep. Bill Cassidy, of Baton Rouge, a Keystone supporter and the leading Republican challenger to Landrieu’s re-election this fall. Cassidy actually denounced the vote before it took place, citing the Republican line that it was a meaningless political stunt designed to make Landrieu look good back home, where the pipeline is popular, when it’s obvious Senate Majority Leader Harry Reid, of Nevada, will prevent the bill from coming to the Senate floor (where, truth be told, it would have trouble attracting the 60 votes needed to advance it past a filibuster).

The Landrieu campaign countered by reviving an April news release from Cassidy that pressed the committee to pass a House version of a Keystone bill similar to the Landrieu-Hoeven measure. Cassidy’s side shot back that the actual letter to the committee that he co-signed, and that occasioned the release, called for full Senate approval.

All this may be much ado about not a heck of a lot, economically or environmentally. At least, that seems to be a major takeaway from a State Department report released in January.

The report said that although building the pipeline would support 42,000 jobs directly and indirectly (including 4,000 temporary construction jobs — many of them, presumably, hundreds of miles from Louisiana), the overall total would drop to just 50 jobs once the pipeline is completed in two years.

But the report also said the environmental impact of the pipeline would be negligible, primarily because the “dirty” tar-sands oil likely will be brought to market by some other means (and ultimately burned) even if the Keystone pipeline is not built.

So is the debate largely symbolic?

“I do not disagree that both sides have inflated either the benefits or the negative disadvantages of the pipeline and that it has become symbolic,” Landrieu said in a May interview. “But symbols are important.”

Keystone, she said would demonstrate the willingness of the United States to take seriously its responsibility to invest in the infrastructure necessary for North American energy self-sufficiency.

“The symbolism of this pipeline,” she said, “is as important as the pipeline itself.”

Follow Gregory Roberts of The Advocate Washington bureau on Twitter, @GregRobertsDC. For more coverage of government and politics, follow our Politics Blog at