In a strong op-ed, The New York Times explains why they think President Obama should reject the proposed Keystone XL pipeline:
"A president who has repeatedly identified climate change as one of humanity’s most pressing dangers cannot in good conscience approve a project that — even by the State Department’s most cautious calculations — can only add to the problem."
It really is that simple.
You should read the full op-ed for the rest of their argument. Plus, seeing how The Times recently shut down their environmental desk and their green blog, by clicking through to read it on their site, you aren't just getting the whole story, you are also "voting with your pageview" so to speak, which will tell the traffic crunchers at The Times that you are interested in this editorial and environmental journalism. There's value in that.