Complex sentence: Smith ran for the vacant 8th congressional district of Missouri seat after incumbent Republican U.S. Representative Jo Ann Emerson resigned to accept a CEO position with the National Rural Electric Cooperative Association.
Split into simpler sentences: Smith ran for the vacant 8th congressional district of Missouri seat after Republican incumbent Jo Ann Emerson resigned. Congresswoman Emerson left her elected position in order to accept the presidency of the National Rural Electric Cooperative Association.