A bit late responding to this and posting from my phone so there may be some typos...
I would change that to "the existence of a conservative party is essential." In order to remain competitive, the Republican Party has had to become a circus tent to house all the fringe voting blocs. Blocs that are fighting each other for control of the party and compromising their ability to function; the Tea Party holding a gun to John Boehner's head any time he dared to so much as glance across the aisle, or Eric Cantor getting primaried out.
I don't see the Republican Party lasting long if they can't actually follow through with their post-failure hand wringing over demographics. They need to shake off the groups that are sabotaging the party's evolution and make them an object of contempt and derision to all but uneducated white male voters. That means losing an election or two or four or more as they try to make up ground in different demographic groups.
If they try to remain as the circus tent, they're done. You can't win the African American vote when you're hosting white supremacists. You can't win the female vote when you're the home for anti-abortion evangelical zealots. You can't win the Hispanic vote when you're Anti-Immigration Central.
If they can't ditch the fringe groups keeping them afloat while simultaneously dragging them under, then a new conservative party will have to break away, like the current one did from the Whigs.
