I suspect, while still being unwilling to make a full-throttle prediction, that this is the first true shake-up of the two-party (or one party, if you’re a fan of the late Gore Vidal) system since 1848 when the Whigs got Zachary Taylor elected as President and then folded themselves up in shame at what they had done. US politics has been headed this way for some time: the election of ‘brands’ rather than policies.