Complex sentence: He was also one of four Alliance MPs who agreed to sit with the Progressive Conservative caucus after the December 9,2003 creation of the merged Conservative Party, as the Progressive Conservative and Canadian Alliance parliamentary caucuses were not officially merged until a few weeks later.
Split into simpler sentences: He was also one of four Alliance MPs who agreed to sit with the Progressive Conservative caucus after the December 9,2003 creation of the merged Conservative Party. The Progressive Conservative and Canadian Alliance parliamentary caucuses were not officially merged until a few weeks later.