President Barack Obama prepares to tee off while playing golf on Martha’s Vineyard in 2011. (AP)

If you had the opportunity to help 20,000 Americans at little or no cost to you, would you do it?  And if you had the means to add $5.2 billion in revenue to the American economy, again at no cost, would you?

President Barack Obama wouldn’t.

For four years, he’s delayed a decision that would provide $20 billion in private-infrastructure investment, help alleviate skyrocketing gas prices, and create tens of thousands of true shovel-ready jobs (opposed to the fictitious ones Obama created with the stimulus).

But instead of letting America reap these benefits, he’s chosen to play politics on the back of the recently laid off engineer, the construction worker who can’t seem to make ends meet, and the mother who can barely afford to fill her gas tank.

And he could change it all with the swoop of his pen.

The Keystone XL pipeline, a 1,700 mile-long construction between Canada and Texas, would create jobs, add valuable tax revenue, and bring thousands of barrels of oil a day.  The project only needs the president’s signature.  So why won’t the president give the pipeline the go ahead?

Because, quite evidently, the president’s primary concern is not economic growth but placating his base of environmental malcontents.

Just this week, 35,000 activists marched in Washington D.C. to protest Keystone for its contrived environmental impact and its alleged effect on global warming (never mind the fact that 31,000 scientists have signed a public petition saying there is no scientific basis for human gas emissions causing catastrophic global warming).

But instead of shouting and marching in the bitter cold, the protesters’ time would have been better spent researching exactly what they were protesting.

With just a cursory Google search, they would have quickly found that the pipeline has already passed one State Department-commissioned, three-year-long environmental review, meeting 57 safety standard requirements.  The review concluded that Keystone would have minimal environmental impact, a fact that President Obama chose to ignore when he rejected the Keystone application in January 2012.

As the State Department nears the end of yet another environmental review, the ball will be in the president’s court once again.  This time, he would be wise to ignore the uninformed environmental protesters at his doorstep.

But let’s grant for a moment that the protesters are right — that the world is in dire threat from imminent global warming, and the Keystone XL pipeline would only serve to hasten our day of reckoning.  Even if we were to concede this point, the pipeline would still make perfect sense.

Canada has already said that they will extract their oil with or without the pipeline, using the same tar sands oil that activists claim cause global warming.  If Canada can’t send their oil to Texas via the Keystone pipeline, they’ll send it to China via tankers – a much more environmentally dangerous means of transporting oil, the Heritage Foundation reported.  Moreover, China will refine the oil themselves, in refineries guarded by far fewer regulations than U.S. refineries.  An environmentalist’s worse nightmare!

So even if Obama rejects the pipeline again, the alleged effects on global warming will be the same.

Instead of engaging in political pandering on this fairly uncomplicated issue, Obama should take a courageous stand.  The unfounded fallacies of a few should not dictate the real life consequences of many.

For a president who’s supposed to be a warrior for the middle class, this isn’t just outrageous, it’s unacceptable.