OKLAHOMA CITY (AP) - Democrats and Republicans in Oklahoma won't be picking a candidate for U.S. Senate in the June 28 statewide primary election, but all of the state's 266,000 registered independents will have a chance to vote.

Oklahoma's incumbent Republican U.S. Sen. James Lankford didn't draw a single GOP challenger. Two Democrats filed for the seat, but one of them withdrew, leaving Mike Workman of Tulsa as the Democratic nominee.

But Oklahoma's newest official political party - the Libertarian Party - will have two candidates vying for the seat in the primary, and registered independents are invited to participate.

Information technology professional Dax Ewbank of Guthrie and Norman retiree Robert Murphy both are running as registered Libertarians.

The winner will be on the ballot in November with Lankford, Workman and two independents.