John Thune

(Rachel Lippmann/St. Louis Public Radio)

Senator Claire McCaskill of Missouri is co-sponsoring legislation that would end tax breaks for the five largest oil companies in the U.S.

The Democrat-backed measure would cut off Shell, Exxon Mobil, Conoco Philips, BP and Chevron from $2 billion per year in subsidies. McCaskill says the savings would go to pay off the country’s spiraling deficit.