Former Alaska Gov. Sarah Palin (R) has endorsed former Missouri state Treasurer Sarah Steelman's (R) Senate bid, a big boost for the underdog candidate as she heads into an early August primary against businessman John Brunner (R) and former Rep. Todd Akin (R-Mo.).

"Sarah Steelman will fight for all of Missouri and all of us, and that is why we must send her to D.C. this fall," Palin posted on her Facebook page. "As a former state treasurer and state senator, Sarah has often had to stand up to the political establishment – even those in her own party – to stop out of control spending and the destructive debt it leaves in its wake. As a mother of three, Sarah knows that we must cut our unsustainable debt to preserve our children’s future. She’ll fight hard for [agriculture] families against the crushing regulations that the Obama administration has put on them."

Steelman is viewed as the best grassroots campaigner in the primary but has struggled mightily with fundraising, and has just $560,000 in the bank for the home stretch of the race while Brunner has already spent $5 million.

Palin is not the only former governor popular with conservatives who has endorsed in the race: former Arkansas Gov. Mike Huckabee (R) is backing Akin.

The three are vying to be the GOP nominee against Sen. Claire McCaskillClaire Conner McCaskillOvernight Cybersecurity: DHS cyber nominee vows to make election security 'top priority' | CIA to allow lawmakers to review classified info on Haspel | Dems raise security concerns about Trump's phone use Election security dominates hearing for Trump Homeland Security nominee Overnight Cybersecurity: Homeland Security official says Russia likely targeted more than 21 states | Senate approves Trump's NSA chief | Lawmakers unveil bipartisan internet privacy bill MORE (D-Mo.), who is likely to face a tough race no matter who wins the primary.