The tailpipes of U.S. cars, sport utility vehicles (SUVs), and other light trucks emit 20 percent of U.S. global warming pollution in the form of carbon dioxide. Thus, the United States can substantially cut its contribution to global warming if it improves vehicle mileage per gallon by raising the Corporate Average Fuel Economy (CAFE) standards that automobile manufacturers must meet. 

Current CAFE standards--27.5 miles per gallon for cars and 20.7 miles per gallon for SUVs and other light trucks-- already keep millions of tons of carbon dioxide out of the atmosphere by reducing the amount of fossil fuel burned. Although technologies exist to improve fuel economy, the federal government has not significantly altered these standards for more than 10 years. Since 1995, Department of Transportation appropriations bills have included a rider, first introduced by House Republican Whip Tom DeLay (R-TX), barring the Department from using its existing authority to increase CAFE standards. 

During consideration of the Fiscal Year 2000 Transportation appropriations bill, Senators Slade Gorton (R-WA), Dianne Feinstein (D-CA), and Richard Bryan (D-NV) introduced a non-binding resolution expressing the sense of the Senate that the freeze on CAFE standards should end. On September 15, 1999, the Senate defeated the resolution 40–55. YES is the pro-environment vote. 

The intention of the resolution was to demonstrate substantial Senate support for a potential veto of the appropriations bill with its CAFE-freeze rider. Although the 40 votes in favor of the resolution were more than the 34 votes necessary to sustain a veto, President Clinton ultimately signed the bill and the rider into law.