Oil -- what it costs and where it comes from -- is a front-and-center topic for Americans, and especially at this convention, where Sarah Palin is being cast as the governor who takes on Big Oil and taxes it until it cries ''uncle.''

Naturally, then, I'm surprised to see oil being literally thrown away here.

In the form of water bottles.

The plastic in water bottles comes from polyethylene terephthalate, which comes from crude oil. And we all know where oil comes from. It's where it's going that's the problem.

Americans use something above 40 billion plastic water bottles a year. It takes a million and a half barrels of oil to make those bottles, at a price of a hundred dollars a barrel.

And we throw away more than 75 out of every hundred bottles. That amounts to tossing out a million barrels of oil every year.

There are recycling bins every 20 yards or so here in the convention halls in St. Paul. But they're almost all empty. The trash bins, however, are loaded with discarded plastic bottles ... with throwaway oil, heading for the landfill.   

Photo of John McCain sipping from his campaign's supply of plastic water bottles (while campaigning in New Hampshire in January) is by the Times' Jay L. Clendenin.