The Bush administration rejects this approach, arguing that mandatory caps and big cuts in emissions may damage the economy.
The only way to assure such a drawdown is for governments to place a mandatory cap on oil in storage.
It has generally opposed mandatory caps on greenhouse gases.
When asked if the company would accept mandatory caps on greenhouse gases, he responded with a firm maybe.
The proposed mandatory caps follow the failure of automakers to meet voluntary targets set by the commission nine years ago.
And the Senate is inching closer to endorsing a mandatory cap on greenhouse gas emissions.
The president' s opposition to mandatory caps retains strong support on Capitol Hill.
The Clinton team proposed to pay for universal coverage by limiting increases in spending (partly through mandatory caps).
Their aim was to introduce a mandatory cap and trade system for greenhouse gases, as a response to the threat of anthropogenic climate change.
Down the line, Congress may well consider mandatory caps on the number of troops in Iraq, or setting a date for withdrawal.