Complex sentence: However, in late June, Arndt switched party affiliations to become a Democrat, as Secretary of State Chris Nelson would not certify the nomination otherwise, due to a state law requiring all candidates of a particular political party to belong to that party.
Split into simpler sentences: However, in late June, Arndt switched party affiliations to become a Democrat. Nelson claimed it was because of a state law requiring all candidates of a particular political party to belong to that party.