WASHINGTON -- President Bush, facing mounting pressure to bring down gasoline prices, on Tuesday roundly rejected the idea of curtailing purchases of oil for the federal emergency stockpile.

Some Democratic lawmakers have championed the issue, and a Texas Republican, Sen. Kay Bailey Hutchison, joined the cause Tuesday, sending a letter to Mr. Bush urging him to stop buying oil for the Strategic Petroleum Reserve, a set of underground salt domes along the Gulf Coast.

She and 15 other GOP senators, including fellow Texan John Cornyn, argue in the letter that halting those purchases would ease price pressure. Sen. Byron Dorgan, D-N.D., filed legislation a few weeks ago to mandate a halt to SPR purchases.

Mr. Bush dismissed the idea at a Rose Garden news conference, saying it didn’t pass cost-benefit analysis given the risks of terrorist attacks.

“If I thought it would affect the price of oil positively, I would seriously consider it,” he said, noting that purchases for the stockpile amount to 67,000 to 68,000 barrels per day – a tiny fraction of the 85 million barrels in world demand. “I don't think that's going to affect price when you affect 0.1 percent. And I do believe it is in our national interest to get the SPR filled, in case there is a major disruption of crude oil around the world.”

Ms. Hutchison said afterward in a statement that she agrees with Mr. Bush on the need to expand U.S. production by opening the Arctic National Wildlife Refuge to drilling, she sees no need to continue buying oil for the emergency reserve – not with three months’ supply already in hand, and prices so high.

“Over the next four months we will deposit over 8 million barrels into the SPR at a very high price, which is not inconsequential.  We should pause depositing into the SPR and bring this domestically produced oil onto the market,” she said.