While George W. Bush and Al Gore continued to duke it out over the White House, President Clinton exercised his executive authority yesterday by creating a new national monument in northern Arizona and substantially expanding one in central Idaho. The Vermilion Cliffs National Monument in Arizona — 293,000 acres near the Colorado River north of the Grand Canyon — is the 11th monument Clinton has created. Clinton also added 661,000 acres to the 54,440-acre Craters of the Moon National Monument in Idaho. Western Republicans have complained bitterly about Clinton’s monument designations, which altogether have protected more than 4.6 million acres, while conservationists have praised them. Enviros are now pushing Clinton to make the Arctic National Wildlife Refuge in Alaska a national monument, particularly because Bush has said he wants to open the pristine area to oil drilling.