Complex sentence: In 2000, L. Craig Schoonmaker, the leader the party self-declared his candidacy to the presidential elections, but because the party is not officially registered, Schoonmaker's filed for his presidential run as an Independent.
Split into simpler sentences: In 2000, L. Craig Schoonmaker, the leader the party declared his candidacy to the presidential elections. But because the party was not officially registered, Schoonmaker's filed for his presidential run as an Independent.