A Republican state representative ostracized by his party caucus because of a misdemeanor domestic assault conviction has set his sights on an open state Senate seat.

Rep. Mark Olson, an eight-term House member from Big Lake, has filed to run in the Republican primary for the Senate district seat held by Betsy Wergin, who resigned effective next Monday after she was appointed to the Minnesota Public Utilities Commission.

Olson was convicted last summer of misdemeanor domestic assault for causing his wife fear. He was subsequently expelled from the House Republican caucus.

After Republicans in May endorsed former Secretary of State Mary Kiffmeyer to run for his seat, Olson flirted with the idea of running for reelection as an independent.

He decided against it, he said, "because I found it would be difficult in the district to explain why I was running as an independent after people had supported me so long as a Republican."

Olson changed his focus to the Senate seat "after my wife worked on me [to convince me to run] and so many people at the county fair said they were still supporting me," he said.

He will compete against two other Republicans, Jeff Holm and Alison Krueger, in the primary. Democrat Lisa Fobbe also has filed to run. The special Republican primary and the general election in the district will be held the same dates as the statewide primary and general elections, Sept. 9 and Nov. 4, respectively.