Complex sentence: In 1970, Blakeney succeeded Lloyd as leader of the Saskatchewan NDP which was then in opposition and in 1971 he led the party to power defeating Ross Thatcher's conservative Liberal Party government.
Split into simpler sentences: In 1970, Blakeney succeeded Lloyd as leader of the Saskatchewan NDP which was then in opposition. In the 1971 provincial election, he led the party to power, defeating Ross Thatcher's conservative Liberal Party government.