A bill to force approval of the Keystone XL pipeline failed in the U.S. Senate on Tuesday, sparing President Barack Obama from an expected veto of legislation that several fellow Democrats supported. The measure fell just short of the 60 votes needed for passage, despite frantic last-minute lobbying by supporters, especially Democratic Senator Mary Landrieu of Louisiana, who faces a runoff election on Dec. 6. She has staked her hopes of winning a fourth Senate term on the Keystone gambit.