During the 18th Knesset, Ben Ari was a member of the National Union party, until it broke up as elections for the 19th Knesset approached and he co-established the Otzma LeYisrael party.
Dalam Knesset ke-18, Ben Ari menjadi anggota dari partai Serikat National, sampai partai tersebut terpecah saat pemilihan Knesset ke-19 dan ia mendirikan partai Otzma LeYisrael.