Gov. George W. Bush of Texas said today that if he was president, he would bring down gasoline prices through sheer force of personality, by creating enough political good will with oil-producing nations that they would increase their supply of crude.

''I would work with our friends in OPEC to convince them to open up the spigot, to increase the supply,'' Mr. Bush, the presumptive Republican candidate for president, told reporters here today. ''Use the capital that my administration will earn, with the Kuwaitis or the Saudis, and convince them to open up the spigot.''

Implicit in his comments was a criticism of the Clinton administration as failing to take advantage of the good will that the United States built with Kuwait and Saudi Arabia during the Persian Gulf war in 1991. Also implicit was that as the son of the president who built the coalition that drove the Iraqis out of Kuwait, Mr. Bush would be able to establish ties on a personal level that would persuade oil-producing nations that they owed the United States something in return.

''Ours is a nation that helped Kuwait and the Saudis, and you'd think we'd have the capital necessary to convince them to increase the crude supplies,'' he said.