Democratic gubernatorial candidate Chris Koster says this year's election for the state's highest office is a "gut check moment."

Koster launched his general election bid Wednesday at the Cass County Courthouse in Harrisonville, a day after the former Republican state senator easily won the Democratic primary. Koster is a former Cass County prosecutor.

During a rally, Koster said his main message to Missourians will be that the state can be fiscally conservative and socially tolerant.

He criticized GOP opponent Eric Greitens, saying his only political philosophies seem to be "blowing up state government" without specifics about how to reform it.

As self-described conservative outsider making his political debut, Greitens won a four-way primary.

Former Navy SEAL officer Eric Greitens already has a remarkable resume that includes international humanitarian trips and founding a nonprofit to help military veterans find work. Now he can add another item: Republican nominee for Missouri governor.

Greitens won a hard-fought, four-way Republican primary Tuesday for the right to take on Democratic Attorney General Chris Koster in the Nov. 8 general election.

He prevailed with about 35 percent of the vote over businessman John Brunner, longtime Lt. Gov. Peter Kinder and former Missouri House Speaker and U.S. Attorney Catherine Hanaway.

Koster, a former Republican state senator, easily won the Democratic gubernatorial primary.

Greitens cast himself as a conservative outsider in his first political campaign.

Koster, who once served as a Republican state senator, describes himself as a conservative Democrat.

More From AM 1050 KSIS