Exxon has been a major opponent of government actions to reduce carbon emissions. It even went to the point of funding research which undermined the scientific consensus on global warming. Exxon now acknowledges global warming, and it assumes that government will eventually price carbon at around $60 per ton. In addition to its oil business, Exxon also owns a large natural gas business. A government tax on carbon emissions would give its natural gas business a competitive advantage over coal companies. Consequently, the Koch family which has interests in the coal business opposes the stance taken by Exxon. It provides funding to American's For Prosperity which attacks politicians who acknowledge global warming and support efforts to reduce carbon emissions.
The battle between Exxon and the Koch family has a long history. The Koch brothers do not like big oil; they will continue to attack Republican's who support government efforts to reduce carbon emissions. This will create a wedge within the Republican Party between party members who align with Exxon and the blue chip corporations who are also basing their business strategies on the assumption of a carbon tax, and Tea Party aligned Republicans who do not accept global warming and have convinced their base that government intervention into markets is an attack on personal liberty. The Republican Party has historically been the party of big business. It will be difficult for the party to deal with rational businesses like GE, Microsoft etc. who have joined with Exxon in assuming a cost of carbon emissions, and the irrational forces within the Tea Party base who will be reluctant to concede that they have been wrong about global warming.