Senior Capitol Hill Democrats battling the Keystone XL oil sands pipeline are casting the project as a sop to the Koch Brothers, billionaire industrialists who pour money into conservative causes.

But Republicans backing Keystone are playing a billionaire card of their own in the fight over the proposed pipeline, which would bring oil sands crude from Alberta to Gulf Coast refineries.

They’re floating the idea that blocking Keystone would benefit Warren Buffett, the famed investor who supports President Obama and his push to raise taxes on the very wealthy.