The Keystone XL debate shows how radically climate politics has shifted since 2008

The fight over the Keystone XL pipeline has been raging for so long it seems almost routine at this point. This month, Republicans in Congress passed a bill to approve the pipeline once and for all. On Tuesday, President Obama vetoed it, saying he still needed more time to decide. And on and on it goes...

So this is a good moment to step back and appreciate just how truly and deeply unexpected it is that we're even having this fight in the first place.