AUGUSTA — Republicans will choose between a party-mainstream legislator and a teacher who represents the more conservative wing of the party as their nominee in a closely watched state Senate race.

Local party committee members in Kennebec County will choose between Patrick Flood of Winthrop, a four-term House member, and Ryan Wheaton of Pittston, who’s backed by Ron Paul supporters, when they meet Monday evening at the Augusta Civic Center to nominate their candidate in the Senate District 21 race.

The candidate who is chosen will face Democratic candidate David Bustin of Hallowell, a former state legislator who also served as state personnel chief.

Senate District 21 includes Chelsea; Farmingdale; Gardiner; Hallowell; Litchfield; Manchester; Monmouth; Pittston; Randolph; West Gardiner; and Winthrop.

The seat’s current occupant, Republican Sen. Earle McCormick of West Gardiner, has decided not to run.