Lee Castillo — a social worker who assists mentally ill Utahns and proudly points to his past experience working in farm fields and attending public schools — has won the Democratic nomination Tuesday to face eight-term incumbent U.S. Rep. Rob Bishop.

He was leading Kurt Weiland, a veteran and business owner, 57 percent to 43 percent Tuesday in unofficial election results.

Castillo, from Layton, promised in earlier debates to push for wage equity, end tax giveaways to big corporations and support universal health care.

His opponent, Weiland, ran into trouble with the Federal Election Commission over the weekend when it said he had not filed required finance paperwork. The FEC said it could take additional action, such as imposing a fine.

Castillo faces a formidable challenge against Bishop, who was first elected in 2002, and has always won by large margins.

Two years ago, Bishop defeated physician Peter Clemens by a 66-26 percent margin. That was actually closer than his 2014 race, when Bishop defeated Donna McAleer by a 72-25 percent margin.