'Our Merdeka Constitution originally provided for an independent EC to assign seats to each State based on population, and to divide each State into constituencies, such that the number of voters in each constituency should not deviate from the average in that State by more than 15%.
In 1960, the EC did its job so impartially that the Alliance Govt amended the Constitution to try to remove the EC Chairman. It failed.
In 1962, it amended the Constitution to retrospectively annul the 1960 redelineation and to require the EC to submit each new redelineation to the PM for the approval of the Dewan Rakyat, giving the PM a right to make modifications.
The 1962 amendment also changed the rural weightage so that urban constituencies could be up to twice the size of rural constituencies.
In 1973, the Constitution was amended to remove this limit altogether.
Both these amendments were supported by the MCA and MIC...'
Also relevant is gerrymandering...
I think, where gerrymandering was done along racial lines, it does not necessarily work now with the increasing number of Malays supporting Pakatan Rakyat. Just like Project IC which helped BN control Sabah with the help of fast-tracked citizens supporting Umno, BN had to resort to new ways like bribing voters, creating phantom voters, and so on. The overwhelming numbers of voters helped to overcome smaller scale cheating, leaving only marginal cases which enabled BN to win and which will be disputed later.