Complex sentence: The opposition boycotted the election, complaining that the electoral system guaranteed victory for the UMP; in the previous January 2003 parliamentary election, the UMP won all 65 seats even though the opposition won 38% of the vote.
Split into simpler sentences: The opposition boycotted the election, and the UMP won all 65 seats. In boycotting the election, the opposition complained that the electoral system guaranteed victory for the UMP; in the previous January 2003 parliamentary election, the UMP won all 65 seats even though the opposition won 38% of the vote.