JEFFERSON CITY -- Shane Schoeller's campaign for secretary of state got a major influx of cash on Friday, when Republican mega donor and retired investment banker Rex Sinquefield cut him a check for $250,000.

Sinquefield gave Schoeller $150,000 in June.

Schoeller emerged from the three-way Republican primary with a little more than $100,000 left in his campaign bank account. This fall he will face off with Jason Kander, a Kansas City Democrat who as of Aug. 1 reported nearly $900,000 cash on hand.

Sinquefield's interest in the secretary of state's race should come as no surprise. The secretary of state oversees signature verification for initiative petitions and approves the summary voters see on the ballot, and over the years Sinquefield has spent millions supporting various ballot initiatives.

In 2010 alone he spent $11.2 million to bankroll the successful ballot measure campaign that required a regular vote on earnings taxes in Kansas City and St. Louis.

Over the last year he's spent nearly $2.6 million to support a measure eliminating Missouri's income tax and replacing it with a sales tax, an idea that didn't make it on to the 2012 ballot.

Just last week he gave $600,000 to A Safer Missouri, a political committee formed to support a ballot measure that would give St. Louis oversight of its police department. Since the Civil War era the department has been run by a state board composed of four gubernatorial appointees and the mayor.

The donation to Schoeller wasn't the only big donation from Sinquefield that was reported on Friday. He also gave the anti-tax group Missouri Club for Growth $160,000. That's in addition to the $500,000 donation he gave the group in May.