Oklahoma's primary elections on Tuesday put open races for U.S. Senate and governor on the ballot in the deeply conservative state where President Donald Trump's status as party kingmaker faces another test ahead of November's midterms.
In the Senate race, Trump's early backing of Republican U.S. Rep. Kevin Hern for the seat previously held by Homeland Security Secretary Markwayne Mullin kept other potential big challengers at bay in Oklahoma, which hasn't elected a Democratic senator since 1990.
A bigger test of Trump's influence — which has usually proved potent in Republican primaries this year — may come in a crowded race to succeed outgoing Gov. Kevin Stitt.
Trump endorsed former state Sen. Mike Mazzei last month, wading late into a primary that includes several prominent Oklahoma Republicans. They include Attorney General Gentner Drummond, former Oklahoma House Speaker Charles McCall and Chip Keating, the state's former public safety director.
The top four candidates relied heavily on their own funds, contributing $22.5 million, almost 72% of their combined fundraising of more than $31 million, according to campaign finance reports.
It has raised the likelihood of an August runoff if no candidate receives at least 50% of the vote.
In a solidly Republican state, the open races for two of Oklahoma's biggest offices set off a political scramble.
READ MORE: Trump's pick for DHS secretary leaves U.S. Senate vacancy in deep-red Oklahoma
Mullin left the Senate to join Trump's cabinet and replace Kristi Noem, whom the president fired in March over mounting criticism over her leadership at the Department of Homeland Security. Republican Alan Armstrong, an energy executive, is filling the Oklahoma Senate seat for now, but state law prohibits him from seeking a full term as an interim appointee.
Stitt, who been governor since 2019, cannot run again because of term limits — and Trump has seemed eager for him to go.
As head of the National Governors Association, Stitt drew Trump's ire earlier this year over a dispute over invitations to White House events at the group's annual meeting. The fallout led to Trump attacking Stitt on social media as a "RINO," meaning Republican in Name Only.