Complex sentence: Evans has stated on numerous occasions that he believes the Senate works best when it has a "non-government party majority" since the strength of political party discipline that prevents most senators exercising a Conscience vote on issues means a government majority means "government control".
Split into simpler sentences: Evans has stated on numerous occasions that he believes the Senate works best when it has a "non-government party majority". His reasoning is that the strength of political party discipline prevents most senators exercising a Conscience vote and so a government majority means "government control".