Also, if every refinery in the US is already operating under 100% capacity, then how does getting more crude to Texas help us?
Stop, you're being a dumbass. Understand the difference between producing a product, taking it to market, and what is done with that product once it leaves market. The guy that grows the carrot is different than the guy who trucks it, is different that the guy who washes and bundles it, is different than the guy who sells it, is different than the guy the puts it in your salad at Golden Corral.
Refinery capacity is near 100%. Believe or not, they have to be shut down every once in a while for maintenance, EPA colonoscopy, etc. We're literally refining as much oil as we possibly (and safely) can in the US. At $110 p/bbl it needs to go somewhere. Think of, GASP, the lost tax revenues if it stayed in the ground. The cheaper it gets to the refineries the cheaper its costs, the cheaper it is for everyone. Oil is not refined in North Dakota or Canada. It needs to get to market so it can be sold.
There is no sense in arguing the merits of shutting down the pipeline, because outside of the environazis, Obama, and you, everyone knows and agrees it was wrong.