082119 404 One of the candidates running for Democratic nomination for the US Senate in Iowa next year visits Sioux City next Tuesday. Theresa Greenfield of Des Moines will hold a Sioux City campaign event on Tuesday. The meet-and-greet event will take place at 5 p.m. at The Marquee on Fourth St. Greenfield is a real estate agent and one of three Democrats who are running for the seat, which is held by U.S. Sen. Joni Ernst. Ernst was first elected in 2014 and is running for re-election. The