I have thought those thoughts too, but look what the 3 party system did to the UK.
It would not stay a 3-party system for long. Do you have any doubt that if a Tea Party became large enough to contend that the RINO GOPe would not join hands with the DNC and all sing Kumbaya in order to defeat us? The GOP needs to go the way of the Whigs. The sooner the better.