Updated

TULSA, Okla. -- Incumbent Republican Tom Coburn has defeated two challengers from his own party in Tuesday's primary election for a U.S. Senate seat in Oklahoma.

Coburn defeated perennial candidate Evelyn Rogers of Tulsa and retired teacher Lewis Kelly Spring of Hugo.

Coburn's crusades against government spending and waste in Washington have made him the darling of Oklahoma conservatives. The Muskogee physician also has opposed home-state spending projects known as earmarks. He is seeking a second term and says he will not seek a third if he wins this fall.

The Democratic Party primary Tuesday featured political newcomer Mark Myles of Oklahoma City and perennial candidate Jim Rogers of Midwest City. Also in the November general election are independent candidates Stephen Wallace and Ronald Dwyer, who are both from Tulsa.