Both Oklahoma Senate seats will be on the ballot today as Sen. Jim Inhofe announced this year that he planned to resign before his term ends. In the race for Mr. Inhofe’s seat, Mr. Mullin, 45, faces former Democratic U.S. Rep. Kendra Horn, 46, an Oklahoma City lawyer who in 2018 ousted a two-term GOP incumbent from a seat held by Republicans for four decades. But winning a congressional seat in an increasingly diverse and progressive city is different from winning a statewide race in Oklahoma, where registered Republicans now make up more than 50 percent of registered voters, compared with less than 30 percent for Democrats. Most polls show Mr Mullin comfortably beating Ms Horne, Libertarian Robert Murphy and independent Ray Woods. If elected, Mr. Mullin would be the first Native American in the U.S. Senate since former Democratic U.S. Sen. Ben Nighthorse Campbell of Colorado left the Senate in 2005, records show.