The point is that the special interests have deep pockets and have worked themselves deeply into the system. Once a candidate is indebted we are down the rabbit hole again. We need Trump to clean the stables without being beholden to anyone but the American people. Once he has have done some of the grunt work and cleared out some dead wood the special interests will be less a factor.
A lifelong liberal isn’t going to clean up anything.
Cruz is dependent upon small-donor money—those ARE the American people.
If you don’t want donors, you’re going to have to settle for only very wealthy candidates, regardless of the magic you think Trump is going to somehow perform.