In the two rounds of seat re-delineation exercises in 1994 and 2003, many multiethnic mixed seats were created for BN to maximise its multiethnic appeal and to make the most out of the opposition's inability to win across ethnic boundaries.
The BN-controlled media made PAS to be seen to the non-Malays as an anathema to their interests, while DAP as a threat to the Malays. Before 2008, PAS supporters rarely voted for the DAP and vice-versa.
The 2008 general election saw PAS benefiting from outpouring Chinese and Indian support for the "anything but Umno" call while some urban Malays voted for DAP for the first time in their lives. Many multiethnic seats in the states north of Negeri Sembilan and on the west coast of the peninsula fell to the opposition.
How Pakatan can win Johor
Sabah and Johor are the two most crucial battlefields in the 2013 election. While Sabah attracts substantial attention, it could be hampered by seat negotiation and cooperation among the opposition groups. Johor is where the BN representatives may fall like dominoes.
Of Johor's 26 parliamentary seats, only eight have more than 60 percent Malay votes that will be harder to win with the current level of support for Pakatan. No seat in Johor has more than 60 percent Chinese voters.
On the one hand, without 25 percent Malay support, even if the non-Malay swing to Pakatan is huge, the entire momentum may just fizzle out with very few seats gained. Pakatan received only about 20 percent Malay support in Johor during the 2008 general election.
On the other hand, if 35 percent Malay voters support Pakatan in this election, anything could happen. While it is tough to get 35 percent Malay support, it is never impossible.
I am told that a recent opinion poll shows Malay support for Pakatan in Johor to have exceeded 30 percent, though the support varies among parties. The support for PAS is much higher than average while DAP's Malay support is lower than average.
As the election approaches, I believe the gaps will narrow if PAS and DAP, with the help of PKR, are able to convince supporters to vote for each other in the context of the coalition.
From a purely mathematical simulations, this chart on the left indicates the possible scenarios in Johor. This is based on the assumption that Indian support for Pakatan is constant at 50 percent.
Of course these are just simulations on paper. But it shows that Barisan Nasional's castle may crumble if a perfect storm comes into shape. It is also a fresh tsunami alert from the people of Johor to the government who refuses to reform.