Firstly, there is a widespread misunderstanding of the electoral system. Political power is not allocated according to a winner-take-all system but rather Proportional Representation (which means that there is absolutely no difference between a single party opposition to the ANC and a multi-party opposition to the ANC.)
Secondly, but most importantly, a vote for the Cape Party is a vote for Cape independence and is the strongest possible vote against the ANC.
The DA categorically rejects the idea of Cape independence. A vote for the DA will simply delay independence to the day when ANC-supporting constituents will form the majority of the Cape. At which point, the DA will have lost their power in the Western Cape and any chance of Independence will be gone as well.
We have received many questions from the voting public expressing support for the idea of Cape Independence, but questioning whether or not it was counter-productive to vote for the Cape Party due to the possible damages it could cause to the DA (‘anything-but-the ANC’). Implied in many of these questions is the belief that “To weaken the DA would be to strengthen the ANC”, strengthening the ANC would be to elect an ANC government in the Cape – a falsely perceived consequence of supporting Cape Independence.
Thus the theory goes, while we support independence, we don’t want to weaken the DA, so we will continue to vote for them.
SA elects representatives according to a system called Proportional Representation (PR). Under this voting system every vote against the ANC counts against the ANC. There is no way that the ANC will benefit out of votes going to another party unless they are in an alliance with that party. Therefore every vote that the Cape Party wins will be automatically added to the coalition that opposes the ANC.
For example, if the Cape Party wins 10% of the vote and the DA wins 45%, collectively that forms a 55% majority for parties opposed to the ANC.
Furthermore, the DA is a party with national ambitions who hold the belief that they will overthrow the ANC and win a national election in South Africa and become the governing political party of South Africa. Ones perspective on the possibilities of this aside, the DA has self-imposed national obligations and as a result is limited in the extent to which they can resist, or wish to resist, the types of ANC policies that directly discriminate against the majority of the people of the Cape.
The Cape Party, however, receives its sole mandate from the Cape, and it is the Cape whom we serve first and foremost. The Cape Party can oppose the types of ANC legislation and policy that the DA is obliged to accept.
Therefore, a vote for the Cape Party will not weaken the opposition toward the ANC, quite the contrary; it will only strengthen the opposition.