Rocky Mountain News: Clean coal is a buzzword in political circles. On the campaign trail, both presidential candidates tout the virtues of clean coal. “And we must find a way to stop coal from polluting our atmosphere without pretending that our nation’s most abundant energy source will just go away. It won’t,” Sen. Barack Obama said in Portsmouth, N.H., this month. “That’s why we must invest in clean coal technologies that we can use at home and share with the world.” Democrat Obama has …