HARRISBURG — A state senator from York County announced his resignation Monday from the seat he held since 1998 and was named executive director of the state Farm Show Complex and Expo Center.

The lieutenant governor immediately scheduled a March 18 special election for the district being vacated by Sen. Mike Waugh, who had previously announced he was not seeking another term.

The state constitution says that a lawmaker, “during the time for which he was elected,” may not be “appointed to any civil office under this commonwealth.” A spokesman for Gov. Tom Corbett said Waugh’s appointment did not violate that provision.

Corbett spokesman Jay Pagni said the job does not qualify as a civil office, as the Farm Show Complex is not a regulatory agency and there is no blanket prohibition on legislators going to work for the state.

He said factors that determine whether a job qualifies as a civil office include the nature of the job, whether its duties are of a grave and important character, if the responsibilities are defined by statute and whether the officer acts under oath.

Local party leaders will determine candidates for the special election, and winning the March vote could give someone an advantage in the May primary and November general election.

Scott Wagner, the owner of a York trash hauling business who had already been running for Waugh’s seat, said he would seek the Republican nomination to run in the special election as well.

Waugh previously represented a York County seat in the state House for six years and was a township supervisor. He owns and operates Glen Ridge Farms and has competed in draft horse competitions at the Farm Show Complex.