The only case where a major party was deposed involved little more than a decapitation of the Whig national committee followed by the creation of Republican state committees formed by the Abolitionists, and whatever Whigs and Democrats who were finally willing to go along with the Abolitionists.
That's how we got the Republican party.
The same trick should work again ~ create a New Republican National Committee and invite the states to send their state chairmen to the NRNC first national meeting.
That ought to pretty much bust up the NRC and their running dog lackeys.
First, a new rule book that sets out to protect the franchise and end the lock the professionals have on what passes for Republican ideology at that point. The way I view this the Socons, Fiscalcons, Countryclubbers and possibly the business interests will need to each have formal internal caucuses that have a veto on candidates for President ~
And the rationalizations continue....