Complex sentence: Long was president of the Ontario Progressive Conservative Party in the late 1980s and played a key role in writing and implementing Mike Harris' "Common Sense Revolution" as well as helping the Tories win the 1995 Ontario election that brought them to power.
Split into simpler sentences: Long was president of the Ontario Progressive Conservative Party in the late 1980s. In that position, he played a key role in writing and implementing party leader Mike Harris' "Common Sense Revolution", and helping the Tories win the 1995 Ontario election that brought them to power.