From left, U.S. Reps. Tracey Mann and Shanice Davids, U.S. Sen. Roger Marshall, and U.S. Reps. Ron Estes and Derek Schmidt are defending their seats against 25 challengers in the August primary election. (Photo illustration by Anna Kaminski/Kansas Reflector)TOPEKA — Thirty candidates are running in August to represent Kansas in the U.S. House and U.S. Senate, including 12 who are seeking to unseat Republican incumbent U.S. Sen. Roger Marshall. O…